LMK04821NKDT [TI]
支持 JESD204B 的超低抖动合成器和抖动消除器 | NKD | 64 | -40 to 85;型号: | LMK04821NKDT |
厂家: | TEXAS INSTRUMENTS |
描述: | 支持 JESD204B 的超低抖动合成器和抖动消除器 | NKD | 64 | -40 to 85 时钟 外围集成电路 晶体 |
文件: | 总128页 (文件大小:4539K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
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LMK04821, LMK04826, LMK04828
SNAS605AS –MARCH 2013–REVISED MAY 2020
LMK0482x Ultra Low-Noise JESD204B Compliant
Clock Jitter Cleaner With Dual Loop PLLs
1 Features
2 Applications
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JEDEC JESD204B Support
Ultra-Low RMS Jitter
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Wireless Infrastructure
Data Converter Clocking
Networking, SONET/SDH, DSLAM
Medical / Video / Military / Aerospace
Test and Measurement
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88 fs RMS Jitter (12 kHz to 20 MHz)
91 fs RMS Jitter (100 Hz to 20 MHz)
–162.5 dBc/Hz Noise Floor at 245.76 MHz
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Up to 14 Differential Device Clocks from PLL2
3 Description
The LMK0482x family is the industry's highest
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Up to 7 SYSREF Clocks
Maximum Clock Output Frequency 3.1 GHz
performance
clock
conditioner
with
JEDEC
LVPECL, LVDS, HSDS, LCPECL
Programmable Outputs from PLL2
JESD204B support.
The 14 clock outputs from PLL2 can be configured to
drive seven JESD204B converters or other logic
devices, using device and SYSREF clocks. SYSREF
can be provided using both DC and AC coupling. Not
limited to JESD204B applications, each of the 14
outputs can be individually configured as high-
performance outputs for traditional clocking systems.
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Up to 1 Buffered VCXO/Crystal Output from PLL1
LVPECL, LVDS, 2xLVCMOS Programmable
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Dual Loop PLLatinum™ PLL Architecture
PLL1
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Up to 3 Redundant Input Clocks
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Automatic and Manual Switch-Over Modes
Hitless Switching and LOS
The high performance, combined with features such
as the ability to trade off between power or
performance, dual VCOs, dynamic digital delay,
holdover, and glitchless analog delay, make the
LMK0482x family ideal for providing flexible high-
performance clocking trees.
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Integrated Low-Noise Crystal Oscillator Circuit
Holdover Mode When Input Clocks are Lost
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PLL2
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Normalized [1 Hz] PLL Noise Floor of
–227 dBc/Hz
Device Information(1)
PART
NUMBER
VCO0
FREQUENCY
VCO1 FREQUENCY
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Phase Detector Rate up to 155 MHz
OSCin Frequency-Doubler
Two Integrated Low-Noise VCOs
2920 to 3080 MHz
LMK04821
1930 to 2075 MHz
VCO1 Div = ÷2 to ÷8
(÷2 = 1460 to 1540 MHz)
50% Duty Cycle Output Divides, 1 to 32
(even and odd)
LMK04826
LMK04828
1840 to 1970 MHz
2370 to 2630 MHz
2440 to 2505 MHz
2920 to 3080 MHz
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Precision Digital Delay, Dynamically Adjustable
25-ps Step Analog Delay
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Multi-Mode: Dual PLL, Single PLL, and Clock
Distribution
Simplified Schematic
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Industrial Temperature Range: –40 to 85°C
Supports 105°C PCB Temperature (Measured at
Thermal Pad)
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3.15-V to 3.45-V Operation
Package: 64-Pin QFN (9.0 mm × 9.0 mm × 0.8
mm)
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
LMK04821, LMK04826, LMK04828
SNAS605AS –MARCH 2013–REVISED MAY 2020
www.ti.com
Table of Contents
9.6 Register Maps ........................................................ 57
9.7 Device Register Descriptions.................................. 61
10 Applications and Implementation.................... 102
10.1 Application Information........................................ 102
10.2 Digital Lock Detect Frequency Accuracy ............ 102
10.3 Driving CLKin and OSCin Inputs......................... 103
10.4 Output Termination and Biasing ......................... 105
10.5 Typical Applications ............................................ 107
10.6 System Examples .............................................. 110
10.7 Do's and Don'ts................................................... 113
11 Power Supply Recommendations ................... 114
11.1 Pin Connection Recommendations..................... 114
1
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Features.................................................................. 1
Applications ........................................................... 1
Description ............................................................. 1
Revision History..................................................... 2
Device Comparison Table..................................... 7
5.1 Device Configuration Information.............................. 7
Pin Configuration and Functions......................... 8
Specifications....................................................... 11
7.1 Absolute Maximum Ratings .................................... 11
7.2 ESD Ratings............................................................ 11
7.3 Recommended Operating Conditions..................... 11
7.4 Thermal Information................................................ 11
7.5 Electrical Characteristics......................................... 12
7.6 SPI Interface Timing ............................................... 25
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7
11.2 Current Consumption / Power Dissipation
Calculations............................................................ 116
12 Layout................................................................. 117
12.1 Layout Guidelines ............................................... 117
12.2 Layout Example .................................................. 118
13 Device and Documentation Support ............... 119
13.1 Device Support .................................................. 119
13.2 Related Links ...................................................... 119
13.3 Trademarks......................................................... 119
13.4 Electrostatic Discharge Caution.......................... 119
13.5 Glossary.............................................................. 119
7.7 Typical Characteristics – Clock Output AC
Characteristics ......................................................... 26
8
9
Parameter Measurement Information ................ 28
8.1 Charge Pump Current Specification Definitions...... 28
8.2 Differential Voltage Measurement Terminology ..... 29
Detailed Description ............................................ 30
9.1 Overview ................................................................. 30
9.2 Functional Block Diagram ....................................... 35
9.3 Feature Description................................................. 39
9.4 Device Functional Modes........................................ 50
9.5 Programming........................................................... 56
14 Mechanical, Packaging, and Orderable
Information ......................................................... 119
4 Revision History
Changes from Revision AR (December 2015) to Revision AS
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Deleted references to "LMK0482xB" and replaced with device names ................................................................................. 1
Updated Pin Configuration and Functions table with expanded descriptions ........................................................................ 8
Changed mVpp to |mV| for 10-mA HSDS VOD in Electrical Characteristics......................................................................... 22
Added requirements for OSCout LVPECL emitter resistors to Detailed Description ........................................................... 30
Changed Overview to provide more detail. .......................................................................................................................... 30
Changed Three PLL1 Redundant Reference Inputs to provide more detail. ....................................................................... 31
Changed Frequency Holdover wording for added clarity. .................................................................................................... 31
Moved VCO1 Divider (LMK04821 only) to within Internal VCOs. ........................................................................................ 31
Changed all instances of '0-delay' to 'zero-delay' and added reference to Multi-Clock Synchronization app note. ............ 33
Changed Figure 10 and Figure 11 to show OSCout_MUX, SYNC/SYSREF detail, and color............................................ 35
Changed Figure 13 to show distribution path reclocking, other FB_MUX targets. .............................................................. 38
Added SYSREF_DDLY_PD and DCLKoutX_DDLY_PD conditions for added power savings in SYNC/SYSREF.............. 39
Added reference to Recommended Programming Sequence.............................................................................................. 40
Changed _CNTH/_CNTL register values to 0, representing delay value of 16, in Table 3. ............................................... 43
Added timing alignment figure, alignment equations to SYSREF to Device Clock Alignment ............................................ 45
Added LOS register requirements to Input Clock Switching - Automatic Mode................................................................... 47
Merged redundant paragraph into Digital Lock Detect. ....................................................................................................... 47
Added note clarifying PLL1 phase detector frequency effect on PLL1_WND_SIZE in Digital Lock Detect......................... 47
Added holdover entry conditions and clarifications in Holdover........................................................................................... 48
Added Single-Loop Mode, Single-Loop Mode With External VCO, Distribution Mode to Device Functional Modes. ......... 50
2
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Product Folder Links: LMK04821 LMK04826 LMK04828
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SNAS605AS –MARCH 2013–REVISED MAY 2020
Revision History (continued)
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Added RESET Pin to Recommended Programming Sequence........................................................................................... 56
Changed CLKoutX_Y_ODL, CLKoutX_Y_IDL, DCLKoutX_DIV descriptions to add more detail........................................ 63
Changed DCLKoutX_ADLY description in DCLKoutX_ADLY, DCLKoutX_ADLY_MUX, DCLKout_MUX........................... 64
Changed SDCLKoutY_ADLY description in SDCLKoutY_ADLY_EN, SDCLKoutY_ADLY. ................................................ 65
Added OSCout LVPECL format instructions in VCO_MUX, OSCout_MUX, OSCout_FMT. ............................................... 68
Changed SYSREF_CLR description in SYSREF_CLR, SYNC_1SHOT_EN, SYNC_POL, SYNC_EN,
SYNC_PLL2_DLD, SYNC_PLL1_DLD, SYNC_MODE to add more detail.......................................................................... 74
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Added time alongside frequency for LOS_TIMEOUT in Table 45 ....................................................................................... 80
Changed LOS_EN description to clarify requirements in Table 45...................................................................................... 80
Changed Table 53, Table 55, Table 56 register text from "N counter" to "R divider" .......................................................... 84
Changed Table 57 maximum field value to match register size........................................................................................... 85
Changed Table 75 headers from Resistance to Capacitance. .......................................................................................... 96
Changed Application Information to reference current TI tools.......................................................................................... 102
Changed all images in Driving CLKin and OSCin Inputs to include OSCin. ..................................................................... 103
Changed CLKinX_BUF_TYPE to CLKinX_TYPE in Driving CLKin and OSCin Pins With a Single-Ended Source. ......... 104
Added Output Termination and Biasing section................................................................................................................. 105
Changed Typical Applications to reference up-to-date tools.............................................................................................. 107
Added System Examples .................................................................................................................................................. 110
Added OSCout, LVDS/HSDS, and RESET pin recommendations to Do's and Don'ts...................................................... 113
Added Pin Connection Recommendations ........................................................................................................................ 114
Deleted empty column in Table 87 and redirected to TICS Pro current calculator............................................................ 116
Changed tools listed in Device Support . ........................................................................................................................... 119
Changes from Revision AQ (August 2014) to Revision AR
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Added Support for 105°C thermal pad temperature............................................................................................................... 1
Changed from I/O to I for pin 6 in Pin Functions table. ......................................................................................................... 8
Deleted programmable status pin in Description column for pin 6 in Pin Functions table..................................................... 8
Changed from No connection to Do not connect for pins 7, 8, 9 in Pin Functions table. ..................................................... 9
Changed to Reference Clock Input Port 1 for PLL 1 for Pins 34, 35 in Pin Functions. ........................................................ 9
Added Reference Clock Input Port 2 for PLL1 for pins 40, 41 in Pin Functions. ................................................................ 10
Added ESD Ratings.............................................................................................................................................................. 11
Added PCB temperature in Recommended Operating Conditions. ..................................................................................... 11
Added Digital Input Timing in Electrical Characteristics. ..................................................................................................... 24
Changed Detailed block diagrams for LMK04821 and LMK04826/8. ................................................................................. 35
Added 6 to DCLKout0 sequence and 7 to SDCLKout1 sequence in Figure 12................................................................... 37
Added 6 to DCLKout0 sequence and 7 to SDCLKout1 sequence in Figure 13................................................................... 38
Added For each SDCLKoutY being used in SYNC/SYSREF............................................................................................... 39
Deleted "SDCLKoutY_PD as required per output. " in Table 1............................................................................................ 39
Added footnote starting SDCLKoutY_PD = 0 as... in Table 1. ............................................................................................ 39
Added SDCLKout1_PD = 0, SDCLKout3_PD = 0 in Setup of SYSREF Example............................................................... 40
Changed DLD_HOLD_CNT to HOLDOVER_DLD_CNT in Holdover Mode - Automatic Exit of Holdover . ........................ 49
Changed Recommended Programming Sequence. ............................................................................................................ 56
Added 0x171/0x172 to Register Map. ................................................................................................................................. 60
Added LMK04821 register setting. ....................................................................................................................................... 62
Revised Register 0x143 table............................................................................................................................................... 74
Copyright © 2013–2020, Texas Instruments Incorporated
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Product Folder Links: LMK04821 LMK04826 LMK04828
LMK04821, LMK04826, LMK04828
SNAS605AS –MARCH 2013–REVISED MAY 2020
www.ti.com
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Added fixed register setting for 0x171.................................................................................................................................. 75
Added fixed register setting for 0x172 ................................................................................................................................. 75
Added LMK04821 register setting. ...................................................................................................................................... 98
Added LMK04821 register setting. ...................................................................................................................................... 99
Changed RB_PLL1_LD description. .................................................................................................................................... 99
Changed RB_PLL2_LD description. .................................................................................................................................... 99
Changes from Revision AP (June 2013) to Revision AQ
Page
•
Changed data sheet flow and layout to conform with new TI standards. Added, updated, or renamed the following
sections: Device Information Table, Application and Implementation; Power Supply Recommendations; Layout;
Device and Documentation Support; Mechanical, Packaging, and Ordering Information .................................................... 1
Added values for LMK04821 under "Features" section. ........................................................................................................ 1
Changed LMK04820 family to LMK0482x family. ................................................................................................................. 1
Added values for LMK04821 in Device Configuration Information......................................................................................... 7
Added holdover DAC to pin 36 description in Pin Functions. ............................................................................................... 9
Changed Thermal Information header from LMK0482xB to LMK0482x. ............................................................................ 11
Changed CLKinX_BUF_TYPE to CLKinX_TYPE in Electrical Characteristics. ................................................................... 12
Added values for LMK04821 under Internal VCO Specifications in Electrical Characteristics. ........................................... 15
Added values for LMK04821 under Noise Floor in Electrical Characteristics...................................................................... 16
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Added values for LMK04821 under CLKout Closed Loop Phase Noise Specifications a Commercial Quality VCXO
in Electrical Characteristics. ................................................................................................................................................. 17
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Added 245.76 MHz as frequency for LMK04826B phase noise data L(f)CLKout for VCO0. .................................................. 18
Added 245.76 MHz as frequency for LMK04826B phase noise data L(f)CLKout for VCO1. .................................................. 18
Added 245.76 MHz as frequency for LMK04828B phase noise data L(f)CLKout for VCO0. .................................................. 18
Added 245.76 MHz as frequency for LMK04828B phase noise data L(f)CLKout for VCO1. .................................................. 18
Added values for LMK04821 under CLKout Closed Loop Jitter Specifications a Commercial Quality VCXO. ................... 19
Added SDCLKoutY_HS = 0 for tsJESD204B in Electrical Characteristics. ............................................................................... 21
Added Propagation Delay from CLKin0 to SDCLKoutY in Electrical Characteristics........................................................... 21
Added footnote that LMK04821 has no DCLKoutX or SDCLKoutY outputs on at power up, only OSCout. ...................... 21
Changed VOH TEST CONDITIONS to = 3 or 4 and VOL TEST CONDITIONS to 3, 4, or 6 under DIGITAL OUTPUTS
(CLKin_SELX, Status_LDX, and RESET/GPO) subheading in Electrical Characteristics................................................... 23
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Changed Digital Inputs (SCK, SDIO, CS*) IIH VIH = VCC min line from 5 µA to –5 µA........................................................ 24
Added 4 wire mode read back has same timing as SDIO pin, R/W bit = 0 is for SPI write, R/W bit = 1 is for SPI
read, W1 and W0 shall be written as 0. ............................................................................................................................... 25
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Added LMK04821 phase noise graphs under Clock Output AC Characteristics. ................................................................ 26
Added link to AN-912 Application Report............................................................................................................................. 29
Changed from Glitchless Half Shift to Glitchless Half Step.................................................................................................. 33
Added LMK04821 detailed block diagram............................................................................................................................ 35
Changed block from SDCLKoutY_POL to DCLKoutX_POL in Figure 12. ........................................................................... 37
Added SYSREF_CLKin0_MUX block to Figure 13 image. .................................................................................................. 38
Changed Figure 13 to show that FB_MUX SYSREF input comes from SYSREF Divider, not SYSREF_MUX.................. 38
Changed term pulsor to pulser throughout........................................................................................................................... 39
Changed DCLKout0_1_DIV to DCLKout0_DIV; DCLKout2_3_DIV to DCLKout2_DIV; DCLKout4_5_DIV to
DCLKout4_DIV. .................................................................................................................................................................... 40
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Added DCLKout4_DIV = 20. ................................................................................................................................................ 40
Added DCLKout0_DDLY_PD = 0, DCLKout2_DDLY_PD = 0, DCLKout4_DDLY_PD = 0.................................................. 40
Changed text to read, Set device clock and SYSREF divider digital delays: DCLKout0_DDLY_CNTH,
DCLKout0_DDLY_CNTL, DCLKout2_DDLY_CNTH, DCLKout2_DDLY_CNTL, DCLKout4_DDLY_CNTH,
4
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Product Folder Links: LMK04821 LMK04826 LMK04828
LMK04821, LMK04826, LMK04828
www.ti.com
SNAS605AS –MARCH 2013–REVISED MAY 2020
DCLKout4_DDLY_CNTL, SYSREF_DDLY. ........................................................................................................................ 40
Added = 1 in SYSREF Request. ......................................................................................................................................... 41
Changed step numbers in dynamic delay and references to steps to be correct, step 8 was duplicated. ......................... 44
Added note LMK04821 includes VCO1 divider on VCO1 output......................................................................................... 50
Added note LMK04821 includes VCO1 divider on VCO1 output......................................................................................... 51
Added R/W bit = 0 is for SPI write. R/W bit = 1 is for SPI read. ......................................................................................... 56
Added If using LMK04821, program register 0x174 in Recommended Programming Sequence. ..................................... 56
Added SYSREF_CLKin0_MUX and VCO1_DIV to register map......................................................................................... 58
Added CLKin_OVERRIDE bit to register map. .................................................................................................................... 59
Changed from half shift to half step...................................................................................................................................... 64
Changed definition of SDCLKoutY_DDLY value of 0 from Reserved to Bypass. ................................................................ 64
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Changed from Sets the polarity of SYSREF clocks to Sets the polarity of clock on SDCLKoutY when device clock
output is selected with SDCLKoutY_MUX............................................................................................................................ 67
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Changed Sets the polarity of the device clocks to Sets the polarity of the device clocks from the DCLKoutX outputs. ..... 67
Added LMK04821 DCLKoutX_FMT power on reset values as powerdown......................................................................... 67
Changed from SYSREF to SYSREF Divider in Source column of Register 0x13F. ........................................................... 71
Changed reserved to Off for CLKin1_OUT_MUX. .............................................................................................................. 76
Changed reserved to Off for CLKin0_OUT_MUX. .............................................................................................................. 76
Added CLKin_OVERRIDE bit............................................................................................................................................... 83
Added LMK04821 register 0x174 for VCO1_DIV................................................................................................................. 98
Deleted LMK04828 from Core line. ................................................................................................................................... 116
Added VCO1 Icc including VCO1 Divider for LMK04821................................................................................................... 116
Changed VCO1 Icc and power dissipated for LMK04828B/26B from 6 mA to 13.5 mA and 19.8 mW to 44.55 mW. ...... 116
Changes from Revision AO (March 2013) to Revision AP
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Changed datasheet title from LMK04828 to LMK0482xB ...................................................................................................... 1
Changed LMK04828 family to LMK04820 family. .................................................................................................................. 1
Changed image from LMK04828B to LMK0482xB. ............................................................................................................... 1
Added LMK04826 to Device Configuration Information table. ............................................................................................... 7
Changed - increased LMK04828B VCO0 max frequency from 2600 MHz to 2630 MHz. ..................................................... 7
Changed - expanded LMK04828B VCO1 frequency range from 2945 - 3005 MHz to 2920 MHz - 3080 MHz..................... 7
Changed Thermal Information header from LMK04828B to LMK0482xB............................................................................ 11
Added LMK04826 VCO Range Specification....................................................................................................................... 15
Changed - increased LMK04828B VCO0 max frequency from 2600 MHz to 2630 MHz. ................................................... 15
Changed - expanded LMK04828B VCO1 frequency range from 2945 - 3005 MHz to 2920 MHz - 3080 MHz................... 15
Added LMK04826 KVCO specification. .................................................................................................................................. 15
Added clarification of LMK04828 specification vs LMK04826 specification for KVCO........................................................... 15
Added LMK04826 noise floor data. ...................................................................................................................................... 16
Changed - clarified phase noise data section header. ......................................................................................................... 17
Added LMK04826 phase noise data. ................................................................................................................................... 18
Added LMK04826 jitter data................................................................................................................................................. 19
Added LMK04826 fCLKout-startup spec. ..................................................................................................................................... 21
Added clarification of LMK04828 specification vs. LMK04826 specification for fCLKout-startup. ................................................ 21
Added LMK04826B Phase Noise Performance Graph for VCO0. ....................................................................................... 26
Added LMK04826B Phase Noise Performance Graph for VCO1. ....................................................................................... 26
Added Added PLL2 loop filter bandwidth and phase margin info to plot. ............................................................................ 27
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SNAS605AS –MARCH 2013–REVISED MAY 2020
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Changed LMK04828 to LMK0482xB in VCXO/Crystal Buffered Output. ............................................................................ 31
Changed LMK04828 to LMK0482xB in Status Pins. ........................................................................................................... 33
Changed image from LMK04828 to LMK0482xB................................................................................................................. 50
Changed - corrected value of PLL2_P selection to be 0 to correspond with register programming definition. ................... 50
Changed image from LMK04828 to LMK0482xB................................................................................................................. 51
Changed image from LMK04828 to LMK0482xB................................................................................................................. 52
Added LMK04826 register setting. ....................................................................................................................................... 62
Added LMK04826 register setting. ....................................................................................................................................... 98
Added LMK04826 register setting. ....................................................................................................................................... 99
6
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SNAS605AS –MARCH 2013–REVISED MAY 2020
5 Device Comparison Table
5.1 Device Configuration Information
PLL2
REF-
OSCout (BUFFERED
OSCin Clock) LVDS/
LVPECL/ LVCMOS
PROGRAMMABLE
LVDS/LVPECL/HSDS
OUTPUTS
ERENCE
PART NUMBER
VCO0 FREQUENCY
VCO1 FREQUENCY
(1)
INPUTS(1)
VCO1_DIV = ÷2
1460 to 1540 MHz
VCO1_DIV = ÷3
974 to 1026 MHz
VCO1_DIV = ÷4
730 to 770 MHz
VCO1_DIV = ÷5
584 to 616 MHz
LMK04821
Up to 3
Up to 1
14
1930 to 2075 MHz
VCO1_DIV = ÷6
487 to 513 MHz
VCO1_DIV = ÷7
418 to 440 MHz
VCO1_DIV = ÷8
365 to 385 MHz
LMK04826
LMK04828
Up to 3
Up to 3
Up to 1
Up to 1
14
14
1840 to 1970 MHz
2370 to 2630 MHz
2440 to 2505 MHz
2920 to 3080 MHz
(1) OSCout may also be third clock input, CLKin2.
Copyright © 2013–2020, Texas Instruments Incorporated
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LMK04821, LMK04826, LMK04828
SNAS605AS –MARCH 2013–REVISED MAY 2020
www.ti.com
6 Pin Configuration and Functions
NKD Package
64-Pin WQFN
Top View
Clock Group 0
Clock Group 3
Status_LD2
Vcc10_PLL2
CPout2
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
DCLKout0
DCLKout0*
SDCLKout1
SDCLKout1*
RESET/GPO
SYNC/SYSREF_REQ
NC
1
2
3
Vcc9_CP2
OSCin*
4
5
OSCin
6
Vcc8_OSCin
7
NC
OSCout*/CLKin2*
OSCout/CLKin2
Vcc7_OSCout
8
LLP-64
Top down view
NC
9
Vcc1_VCO
LDObyp1
10
11
12
13
14
15
16
CLKin0*
LDObyp2
CLKin0
SDCLKout3
SDCLKout3*
DCLKout2
DCLKout2*
Vcc6_PLL1
CLKin1*/Fin*/FBCLKin*
DAP
CLKin1/Fin/FBCLKin
Vcc5_DIG
Clock Group 2
Clock Group 1
Pin Functions
PIN
I/O(1)
DESCRIPTION(2)
NO.
NAME
1
DCLKout0
DCLKout0*
SDCLKout1
Device clock output 0. Differential clock output. Part of clock group 0. To minimize noise, keep all outputs in the clock
group at the same frequency, or at frequencies without spurious interference. If unused, set output format buffer to
powerdown and leave pins floating.
O
2
3
4
SYSREF / Device clock output 1. Differential clock output. Part of clock group 0. To minimize noise, keep all outputs in
the clock group at the same frequency, or at frequencies without spurious interference. If unused, set output format
buffer to powerdown and leave pins floating.
O
SDCLKout1*
RESET/GPO
Device reset input or GPO. If used as a reset input, pin polarity and nominal 160-kΩ pull-up or pull-down are controlled
by register settings. If used as an output, can be set to push-pull or open-drain.
5
6
I/O
I
Synchronization input.. Can be used to reset dividers, trigger the SYSREF pulser, or request continuous SYSREF from
the SYSREF divider. Pin polarity is controlled by register settings. Nominal 160-kΩ pulldown.
SYNC/SYSREF_REQ
(1) The definitions below define the I/O type for each pin.
(a) I = Input
(b) O = Output
(c) I/O = Input / Output (Configurable)
(d) P = Power Supply
(e) BP = Bypass (LDO output)
(f) G = Ground
(g) NC = No Connect
(2) See Pin Connection Recommendations for recommended connections.
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Pin Functions (continued)
PIN
I/O(1)
DESCRIPTION(2)
NO.
7,
NAME
-
-
-
NC
NC
NC
8
Do not connect. These pins must be left floating.
9
Power supply for VCO LDO. Decoupling capacitance requirements may change with system frequency. See Pin
Connection Recommendations for recommendations.
10
Vcc1_VCO
P
11
12
13,
LDObyp1
LDObyp2
SDCLKout3
BP
BP
LDO bypass. This pin must be bypassed to ground with 10-µF capacitor placed close to the pin.
LDO bypass.This pin must be bypassed to ground with a 0.1-µF capacitor placed close to the pin.
SYSREF / Device clock output 3. Differential clock output. Part of clock group 1. To minimize noise, keep all outputs in
the clock group at the same frequency, or at frequencies without spurious interference. If unused, set output format
buffer to powerdown and leave pins floating.
O
14
15
16
SDCLKout3*
DCLKout2
Device clock output 2. Differential clock output. Part of clock group 1. To minimize noise, keep all outputs in the clock
group at the same frequency, or at frequencies without spurious interference. If unused, set output format buffer to
powerdown and leave pins floating.
O
P
DCLKout2*
Power supply for clock outputs 2 and 3. Decoupling capacitance requirements may change with system frequency. See
Pin Connection Recommendations for recommendations.
17
Vcc2_CG1
18
19
CS*
I
I
SPI Chip select. Active-low input. Must be pulled up externally or actively driven high when not in use.
SCK
SPI clock. Active-high input. Nominal 160-kΩ pulldown.
SPI data. This pin can implement bidirectional I/O. As an output, this pin can be configured for open-drain or push-pull.
Open-drain output requires external pull-up. Register settings can disable the output feature of this pin. Other GPIO pins
can also be configured as SPI MISO (master-in slave-out) for traditional 4-wire SPI.
20
21
SDIO
I/O
P
Power supply for SYSREF divider and SYNC. Decoupling capacitance requirements may change with system
frequency. See Pin Connection Recommendations for recommendations.
Vcc3_SYSREF
22
23
24
25
SDCLKout5
SDCLKout5*
DCLKout4
SYSREF / Device clock output 5. Differential clock output. Part of clock group 2. To minimize noise, keep all outputs in
the clock group at the same frequency, or at frequencies without spurious interference. If unused, set output format
buffer to powerdown and leave pins floating.
O
Device clock output 4. Differential clock output. Part of clock group 2. To minimize noise, keep all outputs in the clock
group at the same frequency, or at frequencies without spurious interference. If unused, set output format buffer to
powerdown and leave pins floating.
O
DCLKout4*
Power supply for clock outputs 4, 5, 6, and 7. Decoupling capacitance requirements may change with system frequency.
See Pin Connection Recommendations for recommendations.
26
Vcc4_CG2
27
28
29
30
DCLKout6
Device clock output 6. Differential clock output. Part of clock group 2. To minimize noise, keep all outputs in the clock
group at the same frequency, or at frequencies without spurious interference. If unused, set output format buffer to
powerdown and leave pins floating.
O
O
DCLKout6*
SDCLKout7
SDCLKout7*
SYSREF / Device clock output 7. Differential clock output. Part of clock group 2. To minimize noise, keep all outputs in
the clock group at the same frequency, or at frequencies without spurious interference. If unused, set output format
buffer to powerdown and leave pins floating.
Programmable status pin. By default, this pin is configured as an active-high output representing the state of PLL1 lock
detect. Other status conditions and output polarity are register-selectable. This pin can be configured for open-drain or
push-pull output.
31
Status_LD1
I/O
Charge pump 1 output. This pin is connected to the external loop filter components for PLL1, and to the VCXO control
voltage pin.
32
33
CPout1
O
P
Power supply for digital circuitry, such as SPI bus and GPIO pins. Decoupling capacitance requirements may change
with system frequency. See Pin Connection Recommendations for recommendations.
Vcc5_DIG
(Default) Reference clock input port 1 for PLL1. Can be configured for DC or AC coupling. Accepts single-ended or
differential clocks. If unused in single-ended configuration, connect to GND with a 0.1-µF capacitor. Leave floating if
both pins are unused. See Driving CLKin and OSCin Inputs for single-ended termination information.
CLKin1
I
I
Feedback input for external clock feedback input (zero–delay mode). Can be configured for DC or AC coupling. Accepts
single-ended or differential clocks. If unused in single-ended configuration, connect to GND with a 0.1-µF capacitor.
Leave floating if both pins are unused. See Driving CLKin and OSCin Inputs for single-ended termination information.
FBCLKin
34
External VCO input (external VCO mode) or Clock Distribution input (distribution mode). Can be configured for DC or
AC coupling. Accepts single-ended or differential clocks. If unused in single-ended configuration, connect to GND with a
0.1-µF capacitor. Leave floating if both pins are unused. See Driving CLKin and OSCin Inputs for single-ended
termination information.
Fin
I
(Default) Reference clock input port 1 for PLL1. Can be configured for DC or AC coupling. Accepts single-ended or
differential clocks. If unused in single-ended configuration, connect to GND with a 0.1-µF capacitor. Leave floating if
both pins are unused. See Driving CLKin and OSCin Inputs for single-ended termination information.
CLKin1*
I
I
Feedback input for external clock feedback input (zero-delay mode). Can be configured for DC or AC coupling. Accepts
single-ended or differential clocks. If unused in single-ended configuration, connect to GND with a 0.1-µF capacitor.
Leave floating if both pins are unused. See Driving CLKin and OSCin Inputs for single-ended termination information.
FBCLKin*
35
External VCO input (external VCO mode) or Clock Distribution input (distribution mode). Can be configured for DC or
AC coupling. Accepts single-ended or differential clocks. If unused in single-ended configuration, connect to GND with a
0.1-µF capacitor. Leave floating if both pins are unused. See Driving CLKin and OSCin Inputs for single-ended
termination information.
Fin*
I
P
I
Power supply for PLL1, charge pump 1, holdover DAC. Decoupling capacitance requirements may change with system
frequency. See Pin Connection Recommendations for recommendations.
36
37
Vcc6_PLL1
CLKin0
Reference clock input port 0 for PLL1. Can also be used as a synchronization input for SYNC/SYSREF. Can be
configured for DC or AC coupling. Accepts single-ended or differential clocks. If unused in single-ended configuration,
connect to GND with a 0.1-µF capacitor. Leave floating if both pins are unused. See Driving CLKin and OSCin Inputs for
single-ended termination information.
38
CLKin0*
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Pin Functions (continued)
PIN
I/O(1)
DESCRIPTION(2)
NO.
NAME
Vcc7_OSCout
Power supply for OSCout port and CLKin2. Decoupling capacitance requirements may change with system frequency.
See Pin Connection Recommendations for recommendations.
39
P
(Default) Buffered output of OSCin port. Defaults to LVPECL. In LVPECL output format, this pin only supports 240-Ω
emitter resistors. If unused, set output format buffer to powerdown and leave pins floating.
OSCout
Reference clock input port 2 for PLL1. Can be configured for DC or AC coupling. Accepts single-ended or differential
clocks. If unused in single-ended configuration, connect to GND with a 0.1-µF capacitor. Leave floating if both pins are
unused. See Driving CLKin and OSCin Inputs for single-ended termination information. Registers must be configured to
set this pin as an input.
40
I/O
I/O
CLKin2
(Default) Buffered output of OSCin port. Defaults to LVPECL. In LVPECL output format, this pin only supports 240-Ω
emitter resistors. If unused, set output format buffer to powerdown and leave pins floating.
OSCout*
CLKin2*
Vcc8_OSCin
Reference clock input port 2 for PLL1. Can be configured for DC or AC coupling. Accepts single-ended or differential
clocks. If unused in single-ended configuration, connect to GND with a 0.1-µF capacitor. Leave floating if both pins are
unused. See Driving CLKin and OSCin Inputs for single-ended termination information. Registers must be configured to
set this pin as an input.
41
42
Power supply for OSCin. Decoupling capacitance requirements may change with system frequency. See Pin Connection
Recommendations for recommendations.
P
I
43
44
OSCin
Feedback to PLL1, reference input to PLL2. Inputs to this pin should be AC-coupled. Accepts single-ended or differential
clocks. If unused in single-ended configuration, connect to GND with a 0.1-µF capacitor. Leave floating if both pins are
unused. See Driving CLKin and OSCin Inputs for single-ended termination information.
OSCin*
Power supply for PLL2 charge pump. Decoupling capacitance requirements may change with system frequency. See
Pin Connection Recommendations for recommendations.
45
46
47
Vcc9_CP2
CPout2
P
O
P
Charge pump 2 output. This pin is connected to the external components of the PLL2 loop filter. If an external VCO is
used, this pin is also connected to the external VCO control voltage pin. Do not route this pin near noisy signals.
Power supply for PLL2. Decoupling capacitance requirements may change with system frequency. See Pin Connection
Recommendations for recommendations.
Vcc10_PLL2
Programmable status pin. By default, this pin is configured as an active-high output representing the state of PLL2 lock
detect. Other status conditions and output polarity are register-selectable. This pin can be configured for open-drain or
push-pull output.
48
Status_LD2
I/O
O
49
50
51
52
SDCLKout9
SDCLKout9*
DCLKout8
SYSREF / Device clock 9. Differential clock output. Part of clock group 3. To minimize noise, keep all outputs in the
clock group at the same frequency, or at frequencies without spurious interference. If unused, set output format buffer to
powerdown and leave pins floating.
Device clock output 8. Differential clock output. Part of clock group 3. To minimize noise, keep all outputs in the clock
group at the same frequency, or at frequencies without spurious interference. If unused, set output format buffer to
powerdown and leave pins floating.
O
P
DCLKout8*
Power supply for clock outputs 8, 9, 10, and 11. Decoupling capacitance requirements may change with system
frequency. See Pin Connection Recommendations for recommendations.
53
Vcc11_CG3
54
55
56
57
DCLKout10
Device clock output 10. Differential clock output. Part of clock group 3. To minimize noise, keep all outputs in the clock
group at the same frequency, or at frequencies without spurious interference. If unused, set output format buffer to
powerdown and leave pins floating.
O
DCLKout10*
SDCLKout11
SDCLKout11*
SYSREF / Device clock output 11. Differential clock output. Part of clock group 3. To minimize noise, keep all outputs in
the clock group at the same frequency, or at frequencies without spurious interference. If unused, set output format
buffer to powerdown and leave pins floating.
O
Programmable status pin. By default this pin is programmed as an active-high input with nominal 160-kΩ pulldown that
selects which CLKin is used as the reference to PLL1 in pin-select mode. If used as an input, pin polarity and nominal
160-kΩ pull-up or pull-down are controlled by register settings. If used as an output, can be set to push-pull or open-
drain.
58
59
CLKin_SEL0
CLKin_SEL1
I/O
Programmable status pin. By default this pin is programmed as an active-high input with nominal 160-kΩ pulldown that
selects which CLKin is used as the reference to PLL1 in pin-select mode. If used as an input, pin polarity and nominal
160-kΩ pull-up or pull-down are controlled by register settings. If used as an output, can be set to push-pull or open-
drain.
I/O
60
61
62
63
SDCLKout13
SDCLKout13*
DCLKout12
SYSREF / Device clock output 13. Differential clock output. Part of clock group 0. To minimize noise, keep all outputs in
the clock group at the same frequency, or at frequencies without spurious interference. If unused, set output format
buffer to powerdown and leave pins floating.
O
O
Device clock output 12. Differential clock output. Part of clock group 0. To minimize noise, keep all outputs in the clock
group at the same frequency, or at frequencies without spurious interference. If unused, set output format buffer to
powerdown and leave pins floating.
DCLKout12*
Power supply for clock outputs 0, 1, 12, and 13. Decoupling capacitance requirements may change with system
frequency. See Pin Connection Recommendations for recommendations.
64
-
Vcc12_CG0
DAP
P
Die attach pad. Connect directly to GND plane through multiple vias to minimize resistive and inductive effects and to
achieve good thermal performance. All power supply pins are referred to the DAP ground.
G
10
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SNAS605AS –MARCH 2013–REVISED MAY 2020
7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
(1)
MIN
MAX
UNIT
(2)
VCC
VIN
Supply voltage
Input voltage
–0.3
3.6
V
(VCC
0.3)
+
–0.3
V
TL
TJ
Lead temperature (solder 4 seconds)
Junction temperature
260
150
°C
°C
Differential input current (CLKinX/X*,
OSCin/OSCin*, FBCLKin/FBCLKin*, Fin/Fin*)
IIN
± 5
mA
MSL
Tstg
Moisture sensitivity level
Storage temperature
3
–65
150
°C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) Never to exceed 3.6 V.
7.2 ESD Ratings
VALUE
±2000
±150
UNIT
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)
Machine Model (MM)
V(ESD)
Electrostatic discharge
V
Charged-device model (CDM), per JEDEC specification JESD22-
C101(2)
±250
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. Manufacturing with
less than 500-V HBM is possible with the necessary precautions. Pins listed as ±2000 V may actually have higher performance.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. Manufacturing with
less than 250-V CDM is possible with the necessary precautions. Pins listed as ±250 V may actually have higher performance.
7.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
–40
TYP
25
MAX UNIT
TJ
Junction temperature
125
85
°C
°C
°C
V
TA
Ambient temperature
TPCB
VCC
PCB temperature (measured at thermal pad)
Supply voltage
105
3.45
3.15
3.3
7.4 Thermal Information
LMK0482x
THERMAL METRIC(1)
NKD (WQFN)
64 PINS
24.3
UNIT
RθJA
Junction-to-ambient thermal resistance(2)
Junction-to-case (top) thermal resistance(3)
Junction-to-board thermal resistance(4)
°C/W
°C/W
°C/W
RθJC(top)
RθJB
6.1
3.5
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report (SPRA953).
(2) The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, High-K board, as
specified in JESD51-7, in an environment described in JESD51-2a.
(3) The junction-to-case(top) thermal resistance is obtained by simulating a cold plate test on the package top. No specific JEDEC-standard
test exists, but a close description can be found in the ANSI SEMI standard G30-88.
(4) The junction-to-board thermal resistance is obtained by simulating in an environment with a ring cold plate fixture to control the PCB
temperature, as described in JESD51-8.
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Thermal Information (continued)
LMK0482x
NKD (WQFN)
64 PINS
0.1
THERMAL METRIC(1)
UNIT
ψJT
Junction-to-top characterization parameter(5)
Junction-to-board characterization parameter(6)
Junction-to-case (bottom) thermal resistance(7)
°C/W
°C/W
°C/W
ψJB
3.5
RθJC(bot)
0.7
(5) The junction-to-top characterization parameter, ΨJT, estimates the junction temperature of a device in a real system and is extracted
from the simulation data for obtaining RθJA, using a procedure described in JESD51-2a (sections 6 and 7).
(6) The junction-to-board characterization parameter, ΨJB estimates the junction temperature of a device in a real system and is extracted
from the simulation data for obtaining RθJA , using a procedure described in JESD51-2a (sections 6 and 7).
(7) The junction-to-case(bottom) thermal resistance is obtained by simulating a cold plate test on the exposed (power) pad. No specific
JEDEC standard test exists, but a close description can be found in the ANSI SEMI standard G30-88.
7.5 Electrical Characteristics
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
CURRENT CONSUMPTION
ICC_PD
Power down supply current
Supply current(1)
1
3
mA
mA
14 HSDS 8-mA clocks enabled
PLL1 and PLL2 locked.
ICC_CLKS
565
665
CLKin0/0*, CLKin1/1*, and CLKin2/2* INPUT CLOCK SPECIFICATIONS
fCLKin
Clock input frequency
Clock input slew rate
Clock input
Differential input voltage
Figure 8
0.001
0.15
750
MHz
V/ns
|V|
(2)
SLEWCLKin
VIDCLKin
20% to 80%
AC coupled
0.5
0.125
1.55
3.1
(3)
VSSCLKin
0.25
Vpp
AC coupled to CLKinX;
CLKinX* AC coupled to ground
CLKinX_TYPE = 0 (bipolar)
0.25
2.4
2.4
Vpp
Clock input
Single-ended input voltage
VCLKin
AC coupled to CLKinX;
CLKinX* AC coupled to ground
CLKinX_TYPE = 1 (MOS)
0.35
Vpp
Each pin AC coupled, CLKin0/1/2
CLKinX_TYPE = 0 (bipolar)
0
55
20
|mV|
|mV|
|mV|
DC offset voltage between
CLKinX/CLKinX* (CLKinX* - CLKinX)
Each pin AC coupled, CLKin0/1
CLKinX_TYPE = 1 (MOS)
|VCLKinX-offset
|
DC offset voltage between
CLKin2/CLKin2* (CLKin2* - CLKin2)
Each pin AC coupled
CLKinX_TYPE = 1 (MOS)
VCLKin- VIH
VCLKin- VIL
High input voltage
Low input voltage
DC coupled to CLKinX;
CLKinX* AC coupled to ground
CLKinX_TYPE = 1 (MOS)
2.0
0.0
VCC
0.4
V
V
FBCLKin/FBCLKin* and Fin/Fin* INPUT SPECIFICATIONS
Clock input frequency for
zero-delay with external feedback.
AC coupled
CLKinX_TYPE = 0 (bipolar)
fFBCLKin
fFin
0.001
0.001
750
MHz
MHz
(4)
Clock input frequency for
external VCO or distribution mode
AC coupled
CLKinX_TYPE = 0 (bipolar)
3100
(1) See the applications section of Power Supply Recommendations for Icc for specific part configuration and how to calculate Icc for a
specific design.
(2) To meet the jitter performance listed in the subsequent sections of this data sheet, the minimum recommended slew rate for all input
clocks is 0.5 V/ns. This is especially true for single-ended clocks. Phase-noise performance begins to degrade as the clock input slew
rate is reduced. However, the device will function at slew rates down to the minimum listed. When compared to single-ended clocks,
differential clocks (LVDS, LVPECL) are less susceptible to degradation in phase-noise performance at lower slew rates, due to their
common-mode noise rejection. However, TI also recommends using the highest possible slew rate for differential clocks to achieve
optimal phase-noise performance at the device outputs.
(3) See Differential Voltage Measurement Terminology for definition of VID and VOD voltages.
(4) Assured by characterization. ATE tested at 2949.12 MHz.
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Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
Single ended
Clock input voltage
TEST CONDITIONS
MIN
TYP
MAX UNIT
AC coupled
CLKinX_TYPE = 0 (bipolar)
VFBCLKin/Fin
0.25
2.0
Vpp
AC coupled; 20% to 80%;
(CLKinX_TYPE = 0)
(2)
SLEWFBCLKin/Fin Slew rate on CLKin
0.15
0.5
V/ns
PLL1 SPECIFICATIONS
fPD1
PLL1 phase detector frequency
40
MHz
µA
VCPout1 = VCC/2, PLL1_CP_GAIN = 0
VCPout1 = VCC/2, PLL1_CP_GAIN = 1
VCPout1 = VCC/2, PLL1_CP_GAIN = 2
…
50
150
250
PLL1 charge
ICPout1SOURCE
(5)
Pump source current
…
VCPout1 = VCC/2, PLL1_CP_GAIN = 14
VCPout1 = VCC/2, PLL1_CP_GAIN = 15
VCPout1=VCC/2, PLL1_CP_GAIN = 0
VCPout1=VCC/2, PLL1_CP_GAIN = 1
VCPout1=VCC/2, PLL1_CP_GAIN = 2
…
1450
1550
–50
–150
–250
…
PLL1 charge
Pump sink current
ICPout1SINK
µA
(5)
VCPout1=VCC/2, PLL1_CP_GAIN = 14
VCPout1=VCC/2, PLL1_CP_GAIN = 15
–1450
–1550
Charge pump
Sink / source mismatch
ICPout1%MIS
ICPout1VTUNE
ICPout1%TEMP
ICPout1 TRI
VCPout1 = VCC/2, T = 25 °C
1%
4%
4%
10%
Magnitude of charge pump current
variation vs. charge pump voltage
0.5 V < VCPout1 < VCC - 0.5 V
TA = 25 °C
Charge pump current vs. temperature
variation
Charge pump TRI-STATE leakage
current
0.5 V < VCPout < VCC - 0.5 V
5
nA
PLL 1/f noise at 10-kHz offset.
Normalized to 1-GHz output
frequency
PLL1_CP_GAIN = 350 µA
PLL1_CP_GAIN = 1550 µA
–117
–118
PN10kHz
PN1Hz
dBc/Hz
PLL1_CP_GAIN = 350 µA
PLL1_CP_GAIN = 1550 µA
–221.5
–223
Normalized phase noise contribution
dBc/Hz
PLL2 REFERENCE INPUT (OSCin) SPECIFICATIONS
(6)
fOSCin
PLL2 reference input
500
2.4
MHz
V/ns
PLL2 reference clock minimum slew
SLEWOSCin
20% to 80%
0.15
0.2
0.5
20
(2)
rate on OSCin
AC coupled; single-ended
(unused pin AC coupled to GND)
VOSCin
Input voltage for OSCin or OSCin*
Vpp
VIDOSCin
VSSOSCin
0.2
0.4
1.55
3.1
|V|
Differential voltage swing
Figure 8
AC coupled
Vpp
DC offset voltage between
OSCin/OSCin* (OSCinX* - OSCinX)
|VOSCin-offset
|
Each pin AC coupled
|mV|
MHz
EN_PLL2_REF_2X = 1(8)
OSCin duty cycle 40% to 60%
;
(7)
fdoubler_max
Doubler input frequency
155
(5) This parameter is programmable.
(6) FOSCin maximum frequency assured by characterization. Production tested at 122.88 MHz.
(7) Assured by characterization. ATE tested at 122.88 MHz.
(8) The EN_PLL2_REF_2X bit enables or disables a frequency doubler mode for the PLL2 OSCin path.
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Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
CRYSTAL OSCILLATOR MODE SPECIFICATIONS
Fundamental mode crystal
ESR = 200 Ω (10 to 30 MHz)
ESR = 125 Ω (30 to 40 MHz)
FXTAL
Crystal frequency range
10
40
MHz
pF
CIN
Input capacitance of OSCin port
–40 to 85 °C
1
PLL2 PHASE DETECTOR and CHARGE PUMP SPECIFICATIONS
(7)
fPD2
Phase detector frequency
155
MHz
µA
VCPout2=VCC/2, PLL2_CP_GAIN = 0
VCPout2=VCC/2, PLL2_CP_GAIN = 1
VCPout2=VCC/2, PLL2_CP_GAIN = 2
VCPout2=VCC/2, PLL2_CP_GAIN = 3
VCPout2=VCC/2, PLL2_CP_GAIN = 0
VCPout2=VCC/2, PLL2_CP_GAIN = 1
VCPout2=VCC/2, PLL2_CP_GAIN = 2
VCPout2=VCC/2, PLL2_CP_GAIN = 3
VCPout2=VCC/2, TA = 25 °C
100
400
(5)
ICPoutSOURCE
PLL2 charge pump source current
1600
3200
–100
–400
–1600
–3200
1%
(5)
ICPoutSINK
PLL2 charge pump sink current
µA
ICPout2%MIS
ICPout2VTUNE
Charge pump sink/source mismatch
10%
10
Magnitude of charge pump current vs. 0.5 V < VCPout2 < VCC - 0.5 V
charge pump voltage variation
4%
4%
TA = 25 °C
Charge pump current vs. temperature
variation
ICPout2%TEMP
ICPout2TRI
Charge pump leakage
0.5 V < VCPout2 < VCC - 0.5 V
PLL2_CP_GAIN = 400 µA
nA
(9)
PLL 1/f noise at 10-kHz offset
Normalized to
.
–118
–121
PN10kHz
PN1Hz
dBc/Hz
PLL2_CP_GAIN = 3200 µA
1-GHz output frequency
PLL2_CP_GAIN = 400 µA
PLL2_CP_GAIN = 3200 µA
–222.5
–227
Normalized phase noise contribution
dBc/Hz
(10)
(9) A specification in modeling PLL in-band phase noise is the 1/f flicker noise, LPLL_flicker(f), which is dominant close to the carrier. Flicker
noise has a 10-dB/decade slope. PN10kHz is normalized to a 10-kHz offset and a 1-GHz carrier frequency. PN10kHz = LPLL_flicker(10
kHz) - 20log(Fout / 1 GHz), where LPLL_flicker(f) is the single side band phase noise of only the flicker noise's contribution to total noise,
L(f). To measure LPLL_flicker(f), it is important to be on the 10-dB/decade slope close to the carrier. A high compare frequency and a
clean crystal are important to isolating this noise source from the total phase noise, L(f). LPLL_flicker(f) can be masked by the reference
oscillator performance if a low power or noisy source is used. The total PLL in-band phase noise performance is the sum of LPLL_flicker(f)
and LPLL_flat(f).
(10) A specification modeling PLL in-band phase noise. The normalized phase noise contribution of the PLL, LPLL_flat(f), is defined as:
PN1HZ=LPLL_flat(f) - 20log(N) - 10log(fPDX). LPLL_flat(f) is the single side band phase noise measured at an offset frequency, f, in a 1-Hz
bandwidth and fPDX is the phase-detector frequency of the synthesizer. LPLL_flat(f) contributes to the total noise, L(f).
14
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SNAS605AS –MARCH 2013–REVISED MAY 2020
Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
INTERNAL VCO SPECIFICATIONS
TEST CONDITIONS
MIN
TYP
MAX UNIT
VCO0
VCO1(11)
VCO0
VCO1
VCO0
VCO1
1930
2920
1840
2440
2370
2920
2075
MHz
3080
LMK04821 VCO tuning range
LMK04826 VCO tuning range
LMK04828 VCO tuning range
LMK04821 fine tuning sensitivity
LMK04826 fine tuning sensitivity
1970
MHz
2505
fVCO
2630
MHz
3080
LMK04821 VCO0
12 to 20
15 to 24
11 to 19
8 to 11
MHz/V
MHz/V
MHz/V
LMK04821 VCO1
LMK04826 VCO0
KVCO
LMK04826 VCO1
LMK04828 VCO0 at 2457.6 MHz
LMK04828 VCO1 at 2949.12 MHz
17 to 27
17 to 23
LMK04828 fine tuning sensitivity
Allowable temperature drift for
After programming for lock, no changes
to output configuration are permitted to
assure continuous lock
|ΔTCL
|
continuous lock
125
°C
(12)
(11) The VCO1 divider, VCO1_DIV in register 0x174, can be programmed to ÷2 to ÷8 resulting in a lower effective VCO frequency range, as
shown in Device Configuration Information.
(12) Maximum allowable temperature drift for continuous lock is how far the temperature can drift in either direction from the value it was at
the time that the 0x168 register was last programmed with PLL2_FCAL_DIS = 0, and still have the part stay in lock. The action of
programming the 0x168 register, even to the same value, activates a frequency calibration routine. This implies the part will work over
the entire frequency range, but if the temperature drifts more than the maximum allowable drift for continuous lock, then it is necessary
to reload the appropriate register to ensure it stays in lock. Regardless of what temperature the part was initially programmed at, the
temperature can never drift outside the frequency range of –40 °C to 85 °C without violating specifications.
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Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
NOISE FLOOR
LVDS
–158.2
–160
HSDS 6 mA
HSDS 8 mA
HSDS 10 mA
–161
–161.4
LMK04821, VCO0, noise floor
20-MHz offset(13)
L(f)CLKout
245.76 MHz
dBc/Hz
LVPECL16 with 240
Ω
–161.6
–162
LVPECL20 with 240
Ω
LVPECL
161.7
–157.1
–158.3
–159
LVDS
HSDS 6 mA
HSDS 8 mA
HSDS 10 mA
–159.2
LMK04821, VCO1, noise floor
20-MHz offset(13)
L(f)CLKout
L(f)CLKout
L(f)CLKout
245.76 MHz
245.76 MHz
245.76 MHz
dBc/Hz
dBc/Hz
dBc/Hz
LVPECL16 with 240
Ω
–158.8
–158.9
LVPECL20 with 240
Ω
LVPECL
–158.8
–158.1
–159.7
–160.8
–161.3
LVDS
HSDS 6 mA
HSDS 8 mA
HSDS 10 mA
LMK04826, VCO0, noise floor
(14)
LVPECL16 with 240
Ω
20-MHz offset
–161.8
–162.0
LVPECL20 with 240
Ω
LCPECL
–161.7
–157.5
–158.9
–159.8
–160.3
LVDS
HSDS 6 mA
HSDS 8 mA
HSDS 10 mA
LMK04826, VCO1, noise floor
(14)
LVPECL16 with 240
Ω
20-MHz offset
–160.8
LVPECL20 with 240
Ω
–160.7
–160.7
LCPECL
(13) Data collected using a Prodyn BIB-100G balun. Loop filter is C1 = 47 pF, C2 = 3.9 nF, R2 = 620 Ω, C3 = 10 pF, R3 = 200 Ω, C4 = 10
pF, R4 = 200 Ω, PLL1_CP = 450 µA, PLL2_CP = 3.2 mA.. VCO0 PLL2 loop filter bandwidth = 288 kHz, phase margin = 72 degrees.
VCO1 Loop filter loop bandwidth = 221 kHz, phase margin = 70 degrees. CLKoutX_Y_IDL = 1, CLKoutX_Y_ODL = 0.
(14) Data collected using a Prodyn BIB-100G balun. Loop filter for PLL2 is C1 = 47 pF, C2 = 3.9 nF, R2 = 620 Ω, C3 = 10 pF, R3 = 200 Ω,
C4 = 10 pF, R4 = 200 Ω, PLL1_CP = 450 µA, PLL2_CP = 3.2 mA.. VCO0 loop filter bandwidth = 303 kHz, phase margin = 73 degrees.
VCO1 Loop filter loop bandwidth = 151 kHz, phase margin = 64 degrees. CLKoutX_Y_IDL = 1, CLKoutX_Y_ODL = 0.
16
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SNAS605AS –MARCH 2013–REVISED MAY 2020
Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
NOISE FLOOR (continued)
LVDS
–156.3
–158.4
–159.3
–158.9
HSDS 6 mA
HSDS 8 mA
HSDS 10 mA
LMK04828, VCO0, noise floor
20-MHz offset
L(f)CLKout
245.76 MHz
dBc/Hz
(15)
LVPECL16 with 240
Ω
–161.6
–162.5
LVPECL20 with 240
Ω
LCPECL
–162.1
–155.7
–157.5
–158.1
–157.7
LVDS
HSDS 6 mA
HSDS 8 mA
HSDS 10 mA
LMK04828, VCO1, noise floor
20-MHz offset
L(f)CLKout
245.76 MHz
dBc/Hz
(15)
LVPECL16 with 240
Ω
–160.3
LVPECL20 with 240
Ω
–161.1
–160.8
LCPECL
CLKout CLOSED LOOP PHASE NOISE SPECIFICATIONS a COMMERCIAL QUALITY VCXO(16)
Offset = 1 kHz
Offset = 10 kHz
–126.9
–133.5
–135.4
–149.8
–158.1
–161.1
Offset = 100 kHz
LMK04821
VCO0
SSB phase noise
245.76 MHz
Offset = 1 MHz
L(f)CLKout
dBc/Hz
(13)
LVDS
HSDS 8 mA
Offset = 10 MHz
LVPECL16 with 240
Ω
–161.7
Offset = 1 kHz
Offset = 10 kHz
Offset = 100 kHz
Offset = 1 MHz
–126.8
–133.4
–135.4
–151.8
–157.2
–159.1
LMK04821
VCO1
SSB phase noise
245.76 MHz
L(f)CLKout
dBc/Hz
(13)
LVDS
HSDS 8 mA
Offset = 10 MHz
LVPECL16 with 240
Ω
–158.9
(15) Data collected using ADT2-1T+ balun. Loop filter is C1 = 47 pF, C2 = 3.9 nF, R2 = 620 Ω, C3 = 10 pF, R3 = 200 Ω, C4 = 10 pF, R4 =
200 Ω, PLL1_CP = 450 µA, PLL2_CP = 3.2 mA.. VCO0 loop filter bandwidth = 344 kHz, phase margin = 73 degrees. VCO1 Loop filter
loop bandwidth = 233 kHz, phase margin = 70 degrees. CLKoutX_Y_IDL = 1, CLKoutX_Y_ODL = 0.
(16) VCXO used is a 122.88-MHz Crystek CVHD-950-122.880.
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Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
CLKout CLOSED LOOP PHASE NOISE SPECIFICATIONS a COMMERCIAL QUALITY VCXO (continued)
Offset = 10 kHz
Offset = 100 kHz
LVDS
–134.8
–135.4
–148.2
LMK04826
VCO0
SSB phase noise
245.76 MHz
HSDS 8 mA
LVPECL16 with 240
Ω
Offset = 1 MHz
–148.6
L(f)CLKout
dBc/Hz
(14)
LVDS
–157.8
–160.4
HSDS 8 mA
Offset = 10 MHz
LVPECL16 with 240
Ω
–161.5
Offset = 10 kHz
Offset = 100 kHz
–134.3
–133.7
–152.5
LVDS
LMK04826
VCO1
SSB phase noise
245.76 MHz
HSDS 8 mA
LVPECL16 with 240
Ω
Offset = 1 MHz
Offset = 10 MHz
–153.6
L(f)CLKout
dBc/Hz
(14)
LVDS
–157.3
–159.6
HSDS 8 mA
LVPECL16 with 240
Ω
–160.5
Offset = 1 kHz
Offset = 10 kHz
Offset = 100 kHz
Offset = 1 MHz
–124.3
–134.7
–136.5
–148.4
–156.4
–159.1
LMK04828
VCO0
SSB phase noise
245.76 MHz
L(f)CLKout
dBc/Hz
(15)
LVDS
HSDS 8 mA
Offset = 10 MHz
LVPECL16 with 240
Ω
–160.8
Offset = 1 kHz
Offset = 10 kHz
Offset = 100 kHz
Offset = 1 MHz
–124.2
–134.4
–135.2
–151.5
–159.9
–155.8
LMK04828
VCO1
SSB phase noise
245.76 MHz
L(f)CLKout
dBc/Hz
(15)
LVDS
HSDS 8 mA
Offset = 10 MHz
LVPECL16 with 240
Ω
–158.1
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SNAS605AS –MARCH 2013–REVISED MAY 2020
Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
CLKout CLOSED LOOP JITTER SPECIFICATIONS a COMMERCIAL QUALITY VCXO(16)
LVDS, BW = 12 kHz to 20 MHz
99
94
HSDS 8 mA, BW = 12 kHz to 20 MHz
LVPECL16 with 240 Ω,
BW = 12 kHz to 20 MHz
LMK04821, VCO0
fCLKout = 245.76-MHz
integrated RMS jitter
96
94
93
fs rms
(13)
LVPECL20 with 240 Ω,
BW = 12 kHz to 20 MHz
LCPECL with 240 Ω,
BW = 12 kHz to 20 MHz
JCLKout
LVDS, BW = 12 kHz to 20 MHz
96
90
HSDS 8 mA, BW = 12 kHz to 20 MHz
LVPECL16 with 240 Ω,
BW = 12 kHz to 20 MHz
LMK04821, VCO1
fCLKout = 245.76-MHz
integrated RMS jitter
92
91
91
fs rms
(13)
LVPECL20 with 240 Ω,
BW = 12 kHz to 20 MHz
LCPECL with 240 Ω,
BW = 12 kHz to 20 MHz
CLKout CLOSED LOOP JITTER SPECIFICATIONS a COMMERCIAL QUALITY VCXO (continued)(16)
LVDS, BW = 100 Hz to 20 MHz
106
104
99
LVDS, BW = 12 kHz to 20 MHz
HSDS 8 mA, BW = 100 Hz to 20 MHz
HSDS 8 mA, BW = 12 kHz to 20 MHz
97
LVPECL16 /w 240 Ω,
BW = 100 Hz to 20 MHz
LMK04826, VCO0
fCLKout = 245.76-MHz
integrated RMS jitter
99
96
fs rms
(14)
LVPECL16 /w 240 Ω,
BW = 12 kHz to 20 MHz
LCPECL /w 240 Ω,
BW = 100 Hz to 20 MHz
100
97
LCPECL /w 240 Ω,
BW = 12 kHz to 20 MHz
JCLKout
LVDS, BW = 100 Hz to 20 MHz
LVDS, BW = 12 kHz to 20 MHz
99
97
92
90
HSDS 8 mA, BW = 100 Hz to 20 MHz
HSDS 8 mA, BW = 12 kHz to 20 MHz
LVPECL16 /w 240 Ω,
BW = 100 Hz to 20 MHz
LMK04826, VCO1
fCLKout = 245.76-MHz
integrated RMS jitter
91
89
92
89
fs rms
(14)
LVPECL20 /w 240 Ω,
BW = 12 kHz to 20 MHz
LCPECL /w 240 Ω,
BW = 100 Hz to 20 MHz
LCPECL /w 240 Ω,
BW = 12 kHz to 20 MHz
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Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
CLKout CLOSED LOOP JITTER SPECIFICATIONS a COMMERCIAL QUALITY VCXO (continued)(16)
LVDS, BW = 100 Hz to 20 MHz
112
109
102
99
LVDS, BW = 12 kHz to 20 MHz
HSDS 8 mA, BW = 100 Hz to 20 MHz
HSDS 8 mA, BW = 12 kHz to 20 MHz
LVPECL16 /w 240 Ω,
BW = 100 Hz to 20 MHz
LMK04828, VCO0
fCLKout = 245.76-MHz
integrated RMS jitter
98
95
96
93
fs rms
(15)
LVPECL20 /w 240 Ω,
BW = 12 kHz to 20 MHz
LCPECL /w 240 Ω,
BW = 100 Hz to 20 MHz
LCPECL /w 240 Ω,
BW = 12 kHz to 20 MHz
JCLKout
LVDS, BW = 100 Hz to 20 MHz
LVDS, BW = 12 kHz to 20 MHz
108
105
98
HSDS 8 mA, BW = 100 Hz to 20 MHz
HSDS 8 mA, BW = 12 kHz to 20 MHz
94
LVPECL16 /w 240 Ω,
BW = 100 Hz to 20 MHz
LMK04828, VCO1
fCLKout = 245.76-MHz
integrated RMS jitter
93
90
91
88
fs rms
(15)
LVPECL20 /w 240 Ω,
BW = 12 kHz to 20 MHz
LCPECL /w 240 Ω,
BW = 100 Hz to 20 MHz
LCPECL /w 240 Ω,
BW = 12 kHz to 20 MHz
20
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SNAS605AS –MARCH 2013–REVISED MAY 2020
Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
DEFAULT POWER on RESET CLOCK OUTPUT FREQUENCY
LMK04826
235
315
Default output clock frequency at
device power on
fCLKout-startup
fOSCout
MHz
(17)(18)
LMK04828
(7)
OSCout frequency
500
25
MHz
|ps|
CLOCK SKEW and DELAY
DCLKoutX to SDCLKoutY
(20)
Same pair, same format
SDCLKoutY_MUX = 0 (device clock)
FCLK = 245.76 MHz, RL= 100 Ω
(19)
AC coupled
|TSKEW
|
Maximum DCLKoutX or SDCLKoutY
to DCLKoutX or SDCLKoutY
FCLK = 245.76 MHz, RL= 100 Ω
AC coupled
(20)
Any pair, same format
SDCLKoutY_MUX = 0 (device clock)
50
SDCLKoutY_MUX = 1 (SYSREF)
SYSREF_DIV = 30
SYSREF_DDLY = 8 (global)
SDCLKoutY_DDLY = 1 (2 cycles, local)
DCLKoutX_MUX = 1 (Div+DCC+HS)
DCLKoutX_DIV = 30
DCLKoutX_DDLY_CNTH = 7
DCLKoutX_DDLY_CNTL = 6
DCLKoutX_HS = 0
SYSREF to device clock setup time
base reference.
See SYSREF to Device Clock
Alignment to adjust SYSREF to
device clock setup time as required.
tsJESD204B
–80
ps
SDCLKoutY_HS = 0
CLKin0_OUT_MUX = 0 (SYSREF mux)
SYSREF_CLKin0_MUX = 1 (CLKin0)
SDCLKout1_PD = 0
SDCLKout1_DDLY = 0 (bypass)
SDCLKout1_MUX = 1 (SR)
EN_SYNC = 1
tPDCLKin0_
SDCLKout1
Propagation delay from CLKin0 to
SDCLKout1
0.65
ns
LVPECL16 /w 240 Ω
fADLYmax
Maximum analog delay frequency
DCLKoutX_MUX = 4
1536
395
MHz
LVDS CLOCK OUTPUTS (DCLKoutX, SDCLKoutY, and OSCout)
VOD
Differential output voltage
|mV|
mV
V
Change in magnitude of VOD for
complementary output states
ΔVOD
VOS
–60
60
1.375
35
T = 25 °C, DC measurement
AC coupled to receiver input
RL = 100-Ω differential termination
Output offset voltage
1.125
1.25
180
Change in VOS for complementary
output states
ΔVOS
|mV|
Output rise time
Output fall time
20% to 80%, RL = 100 Ω, 245.76 MHz
80% to 20%, RL = 100 Ω
TR / TF
ps
ISA
ISB
Output short circuit current - single
ended
Single-ended output shorted to GND
T = 25 °C
–24
–12
24
12
mA
mA
Output short circuit current -
differential
ISAB
Complimentary outputs tied together
(17) OSCout oscillates at start-up at the frequency of the VCXO attached to the OSCin port.
(18) LMK04821 has no DCLKoutX or SDCLKoutY outputs which oscillate at power on. Only OSCout oscillates at power on.
(19) Equal loading and identical clock output configuration on each clock output is required for specification to be valid. Specification not valid
for delay mode.
(20) LVPECL uses a 120-Ω emitter resistor, LVDS and HSDS uses a 560-Ω shunt.
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Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
6-mA HSDS CLOCK OUTPUTS (DCLKoutX and SDCLKoutY)
VCC
1.05
-
VOH
T = 25 °C, DC measurement
Termination = 50 Ω to
VCC - 1.42 V
VCC
1.64
-
VOL
VOD
ΔVOD
Differential output voltage
590
|mV|
Change in VOD for complementary
output states
–80
80 mVpp
8-mA HSDS CLOCK OUTPUTS (DCLKoutX and SDCLKoutY)
Output rise time
Output fall time
245.76 MHz, 20% to 80%, RL = 100 Ω
TR / T F
VOH
170
ps
245.76 MHz, 80% to 20%, RL = 100 Ω
VCC
-
1.26
T = 25 °C, DC measurement
Termination = 50 Ω to
VCC - 1.64 V
VCC
–2.06
VOL
VOD
ΔVOD
Differential output voltage
800
|mV|
Change in VOD for complementary
output states
–115
115 mVpp
10-mA HSDS CLOCK OUTPUTS (DCLKoutX and SDCLKoutY)
VCC
0.99
-
VOH
T = 25 °C, DC measurement
Termination = 50 Ω to
VCC - 1.43 V
VCC
1.97
-
VOL
VOD
ΔVOD
980
|mv|
Change in VOD for complementary
output states
–115
115 mVpp
LVPECL CLOCK OUTPUTS (DCLKoutX and SDCLKoutY)
20% to 80% output rise
RL = 100 Ω, emitter resistors = 240 Ω to
GND
TR / TF
150
ps
DCLKoutX_TYPE = 4 or 5
(1600 or 2000 mVpp)
80% to 20% output fall time
1600-mVpp LVPECL CLOCK OUTPUTS (DCLKoutX and SDCLKoutY)
VCC
1.04
-
VOH
VOL
VOD
Output high voltage
Output low voltage
V
V
DC measurement
Termination = 50 Ω to
VCC - 2.0 V
VCC
1.80
-
Output voltage
Figure 9
760
|mV|
2000-mVpp LVPECL CLOCK OUTPUTS (DCLKoutX and SDCLKoutY)
VCC
1.09
-
VOH
VOL
VOD
Output high voltage
Output low voltage
V
V
DC measurement
Termination = 50 Ω to VCC - 2.3 V
VCC
2.05
-
Output voltage
Figure 9
960
|mV|
LCPECL CLOCK OUTPUTS (DCLKoutX and SDCLKoutY)
VOH
VOL
Output high voltage
Output low voltage
1.57
0.62
V
V
DC measurement
Termination = 50 Ω to 0.5 V
Output voltage
Figure 9
VOD
950
|mV|
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SNAS605AS –MARCH 2013–REVISED MAY 2020
Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
LVCMOS CLOCK OUTPUTS (OSCout)
TEST CONDITIONS
MIN
TYP
MAX UNIT
Maximum frequency
fCLKout
VOH
5-pF load
250
MHz
V
(21)
VCC
-
Output high voltage
1-mA load
1-mA load
0.1
VOL
IOH
IOL
Output low voltage
0.1
V
Output high current (source)
Output low current (sink)
VCC = 3.3 V, VO = 1.65 V
VCC = 3.3 V, VO = 1.65 V
28
28
mA
mA
VCC/2 to VCC/2,
FCLK = 100 MHz, T = 25 °C
DUTYCLK
Output duty cycle(22)
50%
TR
TF
Output rise time
Output fall time
20% to 80%, RL = 50 Ω, CL = 5 pF
80% to 20%, RL = 50 Ω, CL = 5 pF
400
400
ps
ps
DIGITAL OUTPUTS (CLKin_SELX, Status_LDX, and RESET/GPO)
IOH = –500 µA
CLKin_SELX_TYPE = 3 or 4
Status_LDX_TYPE = 3 or 4
RESET_TYPE = 3 or 4
VCC
0.4
-
VOH
High-level output voltage
Low-level output voltage
V
V
IOL = 500 µA
CLKin_SELX_TYPE = 3, 4, or 6
Status_LDX_TYPE = 3, 4, or 6
RESET_TYPE = 3, 4, or 6
VOL
0.4
0.4
DIGITAL OUTPUT (SDIO)
IOH = –500 µA ; During SPI read.
SDIO_RDBK_TYPE = 0
VCC
0.4
-
VOH
VOL
High-level output voltage
Low-level output voltage
V
V
IOL = 500 µA ; During SPI read.
SDIO_RDBK_TYPE = 0 or 1
DIGITAL INPUTS (CLKinX_SEL, RESET/GPO, SYNC, SCK, SDIO, or CS*)
VIH
VIL
High-level input voltage
Low-level input voltage
1.2
–5
VCC
0.4
V
V
DIGITAL INPUTS (CLKinX_SEL)
CLKin_SELX_TYPE = 0,
(high impedance)
5
High-level input current
VIH = VCC
IIH
µA
µA
CLKin_SELX_TYPE = 1 (pull-up)
CLKin_SELX_TYPE = 2 (pull-down)
–5
10
5
80
CLKin_SELX_TYPE = 0,
(high impedance)
–5
5
Low-level input current
VIL = 0 V
IIL
CLKin_SELX_TYPE = 1 (pull-up)
CLKin_SELX_TYPE = 2 (pull-down)
–40
–5
–5
5
DIGITAL INPUT (RESET/GPO)
High-level input current
RESET_TYPE = 2
(pull-down)
IIH
10
80
µA
µA
VIH = VCC
RESET_TYPE = 0 (high impedance)
RESET_TYPE = 1 (pull-up)
–5
–40
–5
5
–5
5
Low-level input current
VIL = 0 V
IIL
RESET_TYPE = 2 (pull-down)
DIGITAL INPUTS (SYNC)
IIH
IIL
High-level input current
Low-level input current
VIH = VCC
VIL = 0 V
25
5
µA
–5
DIGITAL INPUTS (SCK, SDIO, CS*)
(21) Assured by characterization. ATE tested to 10 MHz.
(22) Assumes OSCin has 50% input duty cycle.
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Electrical Characteristics (continued)
(3.15 V < VCC < 3.45 V, –40 °C < TA < 85 °C and TPCB ≤ 105 °C. Typical values at VCC = 3.3 V, TA = 25 °C, at the
Recommended Operating Conditions and are not assured.)
PARAMETER
High-level input current
Low-level input current
TEST CONDITIONS
MIN
–5
TYP
MAX UNIT
IIH
IIL
VIH = VCC
VIL = 0
5
5
µA
µA
–5
DIGITAL INPUT TIMING
tHIGH
RESET pin held high for device reset
25
ns
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7.6 SPI Interface Timing
TEST CONDITIONS
See Figure 1
MIN
10
TYP
MAX
UNIT
ns
tds
Setup time for SDI edge to SCLK rising edge
tdH
Hold time for SDI edge from SCLK rising edge
Period of SCLK
See Figure 1
See Figure 1
See Figure 1
See Figure 1
See Figure 1
10
50(1)
ns
tSCLK
tHIGH
tLOW
tcs
ns
High width of SCLK
25
ns
Low width of SCLK
25
ns
Setup time for CS* falling edge to SCLK rising edge
10
ns
tcH
Hold time for CS* rising edge from SCLK rising edge See Figure 1
SCLK falling edge to valid read back data See Figure 1
30
ns
tdv
20
ns
(1) 20 MHz
Register programming information on the SDIO pin is clocked into a shift register on each rising edge of the SCK
signal. On the rising edge of the CS* signal, the register is sent from the shift register to the register addressed.
A slew rate of at least 30 V/µs is recommended for these signals. After programming is complete, the CS* signal
should be returned to a high state. If the SCK or SDIO lines are toggled while the VCO is in lock, as is
sometimes the case when these lines are shared with other parts, the phase noise may be degraded during this
programming.
4-wire mode read back has same timing as the SDIO pin.
R/W bit = 0 is for SPI write. R/W bit = 1 is for SPI read.
W1 and W0 are written as 0.
SDIO
(WRITE)
A12 to A0,
D7 to D2
R/W
W1
W0
D1
D0
tdS
tdH
SCLK
tcH
tcS
tHIGH
tLOW
tSCLK
SDIO
(Read)
D7 to
D2
D1
D0
Data valid only
during read
tdV
CS*
Figure 1. SPI Timing Diagram
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7.7 Typical Characteristics – Clock Output AC Characteristics
These plots show performance at frequencies beyond the point at which the part is ensured to operate, to give an idea of the
capabilities of the part. They do not imply any sort of ensured specification.
For Figure 2 through Figure 7, CLKout2_3_IDL=1; CLKout2_3_ODL=0; LVPECL20 with 240-Ω emitter resistors; DCLKout2
Frequency = 245.76 MHz; DCLKout2_MUX = 0 (Divider). For Figure 2 through Figure 5, Balun Prodyn BIB-100G. For
Figure 6 and Figure 7, Balun ADT2-1T+.
VCO_MUX = 0 (VCO0)
VCO0 = 1966.08 MHz
DCLKout2_DIV = 8
PLL2 Loop Filter Bandwidth = 288 kHz
PLL2 Phase Margin = 72°
VCO_MUX = 1 (VCO1)
VCO = 2949.12 MHz
DCLKout2_DIV = 6
VCO1_DIV = 0 (÷2)
PLL2 Loop Filter Bandwidth = 221 kHz
PLL2 Phase Margin = 70°
Figure 2. LMK04821 DCLKout2 Phase Noise
Figure 3. LMK04821 DCLKout2 Phase Noise
VCO_MUX = 0 (VCO0)
PLL2 Loop Filter Bandwidth = 303 kHz
PLL2 Phase Margin = 73°
VCO_MUX = 1 (VCO1)
PLL2 Loop Filter Bandwidth = 151 kHz
PLL2 Phase Margin = 64°
VCO0 = 1966.08 MHz
DCLKout2_DIV = 8
VCO = 2457.6 MHz
DCLKout2_DIV = 10
Figure 4. LMK04826 DCLKout2 Phase Noise
Figure 5. LMK04826 DCLKout2 Phase Noise
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Typical Characteristics – Clock Output AC Characteristics (continued)
These plots show performance at frequencies beyond the point at which the part is ensured to operate, to give an idea of the
capabilities of the part. They do not imply any sort of ensured specification.
For Figure 2 through Figure 7, CLKout2_3_IDL=1; CLKout2_3_ODL=0; LVPECL20 with 240-Ω emitter resistors; DCLKout2
Frequency = 245.76 MHz; DCLKout2_MUX = 0 (Divider). For Figure 2 through Figure 5, Balun Prodyn BIB-100G. For
Figure 6 and Figure 7, Balun ADT2-1T+.
VCO_MUX = 0 (VCO0)
VCO0 = 2457.6 MHz
DCLKout2_DIV = 10
PLL2 Loop Filter Bandwidth = 344 kHz
PLL2 Phase Margin = 73°
VCO_MUX = 1 (VCO1)
VCO = 2949.12 MHz
DCLKout2_DIV = 12
PLL2 Loop Filter Bandwidth = 233 kHz
PLL2 Phase Margin = 70°
Figure 6. LMK04828 DCLKout2 Phase Noise
Figure 7. LMK04828 DCLKout2 Phase Noise
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8 Parameter Measurement Information
8.1 Charge Pump Current Specification Definitions
I1 = Charge Pump Sink Current at VCPout = VCC - ΔV
I2 = Charge Pump Sink Current at VCPout = VCC/2
I3 = Charge Pump Sink Current at VCPout = ΔV
I4 = Charge Pump Source Current at VCPout = VCC - ΔV
I5 = Charge Pump Source Current at VCPout = VCC/2
I6 = Charge Pump Source Current at VCPout = ΔV
ΔV = Voltage offset from the positive and negative supply rails. Defined to be 0.5 V for this device.
8.1.1 Charge Pump Output Current Magnitude Variation Vs. Charge Pump Output Voltage
8.1.2 Charge Pump Sink Current Vs. Charge Pump Output Source Current Mismatch
8.1.3 Charge Pump Output Current Magnitude Variation Vs. Ambient Temperature
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8.2 Differential Voltage Measurement Terminology
The differential voltage of a differential signal can be described by two different definitions, which can cause
confusion when reading data sheets or communicating with other engineers. This section addresses the
measurement and description of a differential signal, so that the reader can understand and distinguish between
the two different definitions.
The first definition used to describe a differential signal is the absolute value of the voltage potential between the
inverting and non-inverting signal. The symbol for this first measurement is typically VID or VOD, depending on if
an input or output voltage is being described.
The second definition used to describe a differential signal is to measure the potential of the non-inverting signal
with respect to the inverting signal. The symbol for this second measurement is VSS, and is a calculated
parameter. This signal does not exist in the IC with respect to ground; it only exists in reference to its differential
pair. VSS can be measured directly by oscilloscopes with floating references; otherwise this value can be
calculated as twice the value of VOD, as described in the first description.
Figure 8 illustrates the two different definitions side-by-side for inputs, and Figure 9 illustrates the two different
definitions side-by-side for outputs. The VID and VOD definitions show VA and VB DC levels that the non-inverting
and inverting signals toggle between with respect to ground. VSS input and output definitions show that if the
inverting signal is considered the voltage potential reference, the non-inverting signal voltage potential is now
increasing and decreasing above and below the non-inverting reference. Thus, the peak-to-peak voltage of the
differential signal can be measured.
VID and VOD are often defined as volts (V) and VSS is often defined as volts peak-to-peak (VPP).
V
ID
Definition
V
Definition for Input
SS
Non-Inverting Clock
V
V
A
B
2·V
V
ID
ID
Inverting Clock
= | V - V
V
|
B
V
SS
= 2·V
ID
ID
A
GND
Figure 8. Two Different Definitions for
Differential Input Signals
V
Definition
V
Definition for Output
SS
OD
Non-Inverting Clock
V
V
A
B
2·V
OD
V
OD
Inverting Clock
= | V - V
V
|
B
V
SS
= 2·V
OD
OD
A
GND
Figure 9. Two Different Definitions for
Differential Output Signals
Refer to application note AN-912 Common Data Transmission Parameters and their Definitions (SNLA036) for
more information.
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9 Detailed Description
9.1 Overview
The LMK0482x family are multi-purpose, jitter cleaning dual-PLL circuits, with user-programmable settings to
support a flexible set of configurations for many different application requirements. PLL1 is optimized for use with
an external VCXO as the PLL oscillator, while PLL2 includes a dual-range integrated VCO and distributes the
VCO output to 7 integrated 10-bit channel dividers and a 13-bit SYSREF divider, yielding a total of 14 differential
clock outputs at up to 8 different frequencies.
The primary use case is as a dual-loop jitter cleaner (dual-loop mode), when using a reference clock with good
frequency accuracy but poor phase noise to generate ultra-low jitter output clocks. Dual-loop mode also helps to
maintain a high phase detector frequency and loop bandwidth in the clock generation PLL when the greatest
common divisor of the reference clock frequency and the output clock frequencies is small, avoiding a low phase
detector frequency that would elevate output clock phase noise.
Both PLLs can optionally be disabled. By disabling PLL1, the LMK0482x can be used as a standard single-PLL
clock generator with integrated VCO (single-loop mode). By disabling both PLLs, the LMK0482x can act as a
distribution buffer/divider, directly connecting an input reference to the clock dividers and the SYSREF divider.
The clock output dividers can also be bypassed or set to divide of 1 for distribution only mode.
In a typical dual-loop configuration, the external VCXO is connected to the PLL1 N-divider, and the integrated
VCO is connected to the N-divider directly. However, by routing the divided clock or SYSREF output of PLL2 to
the N-divider of PLL1, PLL2, or both PLLs in a family of configurations called zero-delay mode, the LMK0482x
can establish a deterministic phase relationship between reference input phase and clock output phase. Using
zero-delay mode, multiple LMK0482x can be cascaded to fan out exponentially more outputs, while maintaining
predictable input-to-output phase throughout the whole chain of devices. Zero-delay mode is supported in
singleloop and dual-loop mode, with two dual-loop configurations: nested dual-loop (feedback connected to PLL1
Ndivider) and cascaded dual-loop (feedback connected to PLL2 N-divider).
The LMK0482x may be used in JESD204B sytems by providing a device clock and SYSREF to up to 7 devices.
However, alternate (non-JESD204B) systems are also possible by programming pairs of outputs to share the
clock divider. Any mix of JESD204B and alternate systems can be supported.
9.1.1 Jitter Cleaning
The dual-loop PLL architecture of the LMK0482x family provides the lowest jitter performance over a wide range
of output frequencies and phase-noise integration bandwidths. The first-stage PLL (PLL1) is driven by an
external reference clock, and uses an external VCXO or tunable crystal to provide a frequency accurate, low
phase-noise reference clock for the second-stage frequency multiplication PLL (PLL2).
PLL1 typically uses a narrow-loop bandwidth (10 Hz to 200 Hz) to retain the frequency accuracy of the reference
clock input signal, while at the same time suppressing the higher offset frequency phase noise that the reference
clock may have accumulated along its path or from other circuits. This “cleaned” reference clock provides the
reference input to PLL2.
The low phase-noise reference provided to PLL2 allows PLL2 to operate with a wide-loop bandwidth (typically 50
kHz to 200 kHz). The loop bandwidth for PLL2 is chosen to take advantage of the superior high-offset frequency
phase-noise profile of the internal VCO, and the good low-offset frequency phase noise of the reference VCXO
or tunable crystal.
Ultra low jitter is achieved by allowing the external VCXO or crystal phase noise to dominate the final output
phase noise at low-offset frequencies, and the internal VCO phase noise to dominate the final output phase
noise at high-offset frequencies. This results in best overall phase noise and jitter performance.
9.1.2 JEDEC JESD204B Support
The LMK0482x family provides support for JEDEC JESD204B. The LMK0482x clocks up to 7 JESD204B targets
using 7 device clocks (DCLKoutX) and 7 SYSREF clocks (SDCLKoutY). Each device clock is grouped with a
SYSREF clock.
The user can reprogram SYSREF clocks to behave as extra device clocks for applications which have non-
JESD204B clock requirements.
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Overview (continued)
9.1.3 Three PLL1 Redundant Reference Inputs
The LMK0482x family has up to three reference clock inputs for PLL1. They are CLKin0, CLKin1, and CLKin2.
The active clock is chosen based on CLKin_SEL_MODE. Automatic or manual switching can occur between the
inputs.
CLKin0, CLKin1, and CLKin2 each have their own PLL1 R dividers. CLKin0, CLKin1, and CLKin2 each support
differential or single-ended inputs, and support DC coupling or AC coupling. See Driving CLKin and OSCin
Inputs.
CLKin1 is shared for use as an external zero-delay feedback (FBCLKin), or for use with an external VCO (Fin).
CLKin2 is shared for use as OSCout. To use CLKin2 as an input, OSCout must be powered down. See
VCO_MUX, OSCout_MUX, OSCout_FMT.
Fast manual switching between reference clocks is possible with a external pins CLKin_SEL0 and CLKin_SEL1.
For clock distribution mode, a reference signal is applied to the Fin pins for clock distribution. CLKin0 can also be
used to distribute a SYSREF signal through the device. In this use case, CLKin0 may be re-clocked by Fin, or
can be routed directly to the SYSREF outputs.
9.1.4 VCXO/Crystal Buffered Output
CLKin2 may instead be configured as OSCout, which by default is a buffered copy of the PLL1 feedback/PLL2
reference input (OSCin). This reference input is typically a low-noise VCXO or crystal. When using a VCXO, this
output can be used to clock external devices such as microcontrollers, FPGAs, and CPLDs, before the
LMK0482x is programmed.
The OSCout buffer output type is programmable to LVDS, LVPECL, or LVCMOS. OSCout LVPECL mode only
supports 240-Ω emitter resistors.
The VCXO/crystal buffered output can be synchronized to the VCO clock distribution outputs by using cascaded
zero-delay mode. The buffered output of VCXO/crystal has a deterministic phase relationship with CLKin.
9.1.5 Frequency Holdover
When the reference inputs to PLL1 are lost, the LMK0482x family can enter holdover mode until a valid
reference clock signal is re-established. Holdover mode forces a constant DC voltage output to the control pin of
the PLL1 VCXO, ensuring minimal frequency drift while the reference inputs are absent.
9.1.6 PLL2 Integrated Loop Filter Poles
The LMK0482x family features programmable 3rd- and 4th-order loop filter poles for PLL2. These internal
resistors and capacitor values may be selected from a fixed range of values to achieve either a 3rd- or 4th-order
loop filter response. The integrated programmable resistors and capacitors compliment external components
mounted near the chip.
These integrated components can be effectively disabled by programming the integrated resistors and capacitors
to their minimum values.
9.1.7 Internal VCOs
The LMK0482x family has two internal VCOs, selected by VCO_MUX. The output of the selected VCO is routed
to the clock distribution path. This same selection is also fed back to the PLL2 phase detector through a
prescaler and N-divider.
9.1.7.1 VCO1 Divider (LMK04821 only)
The LMK04821 includes a VCO divider on the output of VCO1. The VCO1 divider can be programmed from 2 to
8.
When using a VCO1 frequency of 2949.12 MHz and a divide of 8, frequencies as low as 11.52 MHz can be
achieved. Using the VCO1_DIV limits the maximum output frequency from any output to the VCO1 frequency,
divided by VCO1_DIV value.
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Overview (continued)
When using VCO1, the output frequency from the VCO1_DIV defines the digital delay resolution.
The VCO1_DIV divider also impacts the total N divide value for PLL2 when VCO1 is selected; this should be
accounted for when selecting PLL2_N and PLL2_P value.
9.1.8 External VCO Mode
The Fin/Fin* input allows an external VCO to be used with PLL2 of the LMK0482x family.
Using an external VCO prevents the use of CLKin1 for other purposes.
9.1.9 Clock Distribution
The LMK0482x family features a total of 14 PLL2 clock outputs, driven from the internal or external VCO.
All PLL2 clock outputs have programmable output types. They can be programmed to LVPECL, LVDS, or HSDS,
or LCPECL.
If OSCout is included in the total number of clock outputs the LMK0482x family is able to distribute, then up to 15
differential clocks. OSCout may be a buffered version of OSCin, DCLKout6, DCLKout8, or SYSREF. Its output
format is programmable to LVDS, LVPECL, or LVCMOS. OSCout LVPECL mode only supports 240-Ω emitter
resistors.
The following sections discuss specific features of the clock distribution channels that allow the user to control
various aspects of the output clocks.
9.1.9.1 Device Clock Divider
Each device clock, DCLKoutX, has a single clock output divider. The divider supports a divide range of 1 to 32
(even and odd) with 50% output duty cycle, using duty cycle correction mode. The output of this divider may also
be directed to SDCLKoutY, where Y = X + 1.
9.1.9.2 SYSREF Clock Divider
The SYSREF clocks, SDCLKoutY, all share a common divider. The divider supports a divide range of 8 to 8191
(even and odd).
9.1.9.3 Device Clock Delay
The device clocks include both a analog and digital delay for phase adjustment of the clock outputs.
The analog delay allows a nominal 25-ps step size, and range from 0 to 575 ps of total delay. Enabling the
analog delay adds a nominal 500 ps of delay, in addition to the programmed value.
The digital delay allows a group of outputs to be delayed from 4 to 32 VCO cycles. The delay step can be as
small as half the period of the clock distribution path. For example, a 2-GHz VCO frequency results in 250 ps
coarse tuning steps. The coarse (digital) delay value takes effect on the clock outputs after a SYNC event.
There are two ways to use the digital delay.
1. Fixed digital delay – Allows all the outputs to have a known phase relationship upon a SYNC event. Typically
performed at startup.
2. Dynamic digital delay – Allows the phase relationships of the clocks to change while the clocks continue to
operate.
9.1.9.4 SYSREF Delay
The global SYSREF divider includes a digital delay block, which allows a global phase shift with respect to the
other clocks.
Each local SYSREF clock output includes both an analog and additional local digital delay, for unique phase
adjustment of each SYSREF clock.
The local analog delay allows for 150-ps steps.
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Overview (continued)
The local digital delay and SYSREF_HS bit allows the each individual SYSREF output to be delayed from, 1.5 to
11 VCO cycles. The delay step can be as small as half the period of the clock distribution path, by using the
DCLKoutX_HS bit. For example, a 2-GHz VCO frequency results in 250 ps coarse tuning steps.
9.1.9.5 Glitchless Half Step and Glitchless Analog Delay
The device clocks include a feature to ensure glitchless operation of the half step and analog delay operations,
when enabled.
9.1.9.6 Programmable Output Formats
For increased flexibility all LMK0482x family device and SYSREF clock outputs, DCLKoutX and SDCLKoutY, can
be programmed to an LVDS, HSDS, LVPECL, or LCPECL output type. The OSCout can be programmed to an
LVDS, LVPECL, or LVCMOS output type. OSCout LVPECL mode only supports 240-Ω emitter resistors.
Any LVPECL output type can be programmed to 1600- or 2000-mVpp amplitude levels. The 2000-mVpp
LVPECL output type is a Texas Instruments proprietary configuration that produces a 2000-mVpp differential
swing for compatibility with many data converters, and is known as 2VPECL.
LCPECL allows for DC coupling SYSREF to low-voltage converters.
9.1.9.7 Clock Output Synchronization
Using the SYNC input causes all active clock outputs to share a rising edge, as programmed by fixed digital
delay.
The SYNC event must occur for digital delay values to take effect.
9.1.10 Zero-Delay
The LMK0482x family supports two types of zero-delay.
1. Cascaded zero-delay
2. Nested zero-delay
Cascaded zero-delay mode establishes a fixed deterministic phase relationship of the phase of the PLL2 input
clock (OSCin) to the phase of a clock selected by the feedback mux. The zero-delay feedback may performed
with an internal feedback from CLKout6, CLKout8, SYSREF, or with an external feedback loop into the FBCLKin
port as selected by the FB_MUX. Because OSCin has a fixed deterministic phase relationship to the feedback
clock, OSCout will also have a fixed deterministic phase relationship to the feedback clock. In this mode, the
PLL1 input clock (CLKinX) also has a fixed deterministic phase relationship to PLL2 input clock (OSCin); this
results in a fixed deterministic phase relationship between all clocks from CLKinX to the clock outputs.
Nested zero-delay mode establishes a fixed deterministic phase relationship of the phase of the PLL1 input clock
(CLKinX) to the phase of a clock selected by the feedback mux. The zero-delay feedback may performed with an
internal feedback from CLKout6, CLKout8, SYSREF, or with an external feedback loop into the FBCLKin port as
selected by the FB_MUX.
Without using zero-delay mode, there are numerous possible fixed phase relationships from clock input to clock
output, depending on the clock output divide value. Careful selection of the zero-delay feedback value can
reduce the number of fixed phase relationships from clock input to clock output, potentially to as few as one. As
a result, zero-delay simplifies input-to-output phase guarantees, especially across multiple devices. For more
information, see the application note Multi-Clock Synchronization.
Using an external zero-delay feedback prevents the use of CLKin1 for other purposes.
9.1.11 Status Pins
The LMK0482x provides status pins, which can be monitored for feedback, or in some cases used for input
depending upon device programming. For example:
•
•
•
The CLKin_SEL0 pin may be configured as an output, indicating the LOS (loss-of-signal) for CLKin0.
The CLKin_SEL1 pin may be configured as an input, for selecting the active clock input.
The Status_LD1 pin may indicate if the device is locked (PLL1 and PLL2 locked).
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Overview (continued)
•
The Status_LD2 pin may indicate if PLL2 is locked.
The status pins can be programmed to a variety of other outputs, including PLL divider outputs, combined PLL
lock detect signals, PLL1 Vtune railing, SPI readback, and so forth. Refer to the programming section of this data
sheet for more information.
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9.2 Functional Block Diagram
Figure 10 and Figure 11 illustrate the complete LMK0482x family block diagram.
Figure 10. Detailed LMK04821 Block Diagram
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Functional Block Diagram (continued)
Figure 11. Detailed LMK04826 and LMK04828 Block Diagram
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Functional Block Diagram (continued)
CLKoutX_Y_PD
DCLKout6/8 to FB_MUX
DCLKoutX_ADLY_PD
DCLKoutX_ADLYg_PD
DCLKoutX_DDLY_PD
DCLKoutX_HSg_PD
DCLKout0, 2, 4, 6, 8, 10, 12
VCO
DDLY Divider
(4 to 32) (1 to 32)
HS/
DCC
DCLKoutX
_MUX
DCLKoutX_
FMT
DCLKoutX
_ADLY
_MUX
Analog
DLY
DDDLYdX_EN
CLKoutX_Y_ODL
SYNC_
1SHOT_EN
CLKoutX_Y_IDL
SYSREF_GBL_PD
SDCLKoutY_DIS_MODE
One
Shot
SDCLKoutY
_POL
SYNC_
DISX
SDCLKoutY_PD
SDCLKoutY
_MUX
SDCLKoutY_
FMT
SDCLKoutY
_ADLY_EN
SYSREF/SYNC
Digital
DLY
Half
Step
Analog
DLY
SDCLKout1, 3, 5, 7, 9, 11, 13
Legend
SYSREF/SYNC Clock
SYSREF_CLR
SPI Register
VCO/Distribution Clock
Figure 12. Device and SYSREF Clock Output Block
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Functional Block Diagram (continued)
Figure 13. SYNC/SYSREF Clocking Paths
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9.3 Feature Description
9.3.1 SYNC/SYSREF
To properly use SYNC or SYSREF for JESD204B, it is important to understand the SYNC/SYSREF system. The
SYNC and SYSREF signals share the same clocking path, with SYNC_DISX bits used to enable the path from
SYSREF/SYNC to each divider reset port. Figure 12 illustrates the detailed diagram of a clock output block with
SYNC circuitry included.Figure 13 illustrates the interconnects and highlights some important registers used in
controlling the device for SYNC/SYSREF purposes.
To reset or synchronize a divider, the following conditions must be met:
1. SYNC_EN must be set. This ensures proper operation of the SYNC circuitry.
2. SYSREF_MUX and SYNC_MODE must be set to a proper combination to provide a valid SYNC/SYSREF
signal.
–
–
–
If SYSREF block is being used, the SYSREF_PD bit must be clear.
If the SYSREF Pulser is being used, the SYSREF_PLSR_PD bit must be clear.
For each SDCLKoutY being used for SYSREF, respective SDCLKoutY_PD bits must be cleared.
3. SYSREF_DDLY_PD and DCLKoutX_DDLY_PD bits must be clear to power up the digital delay circuitry
during SYNC. After the SYNC event, these bits may be set to reduce power consumption.
4. The SYNC_DISX bit must be clear to allow the SYNC/SYSREF signal to reset the divider circuit. The
SYSREF_MUX register selects the SYNC source.
5. Other bits which impact the operation of SYNC, such as SYNC_1SHOT_EN, may be set as desired.
Table 1 illustrates the some possible combinations of SYSREF_MUX and SYNC_MODE.
Table 1. Some Possible SYNC Configurations
NAME
SYNC_MODE
SYSREF_MUX
OTHER
DESCRIPTION
SYNC disabled
0
0
CLKin0_OUT_MUX ≠ 0
No SYNC occurs.
Basic SYNC functionality, SYNC pin polarity is
selected by SYNC_POL.
To achieve SYNC through SPI, toggle the
SYNC_POL bit.
Pin or SPI SYNC
1
0
CLKin0_OUT_MUX ≠ 0
Differential input
SYNC
0 or 1
2
0 or 1
2
CLKin0_OUT_MUX = 0
Differential CLKin0 now operates as SYNC input.
Produce SYSREF_PULSE_CNT programmed
number of pulses on pin transition. SYNC_POL can
be used to cause SYNC through SPI.
JESD204B pulser
on pin transition.
SYSREF_PULSE_CNT
sets pulse count
JESD204B pulser
on SPI
programming.
SYSREF_PULSE_CNT
sets pulse count
Programming the SYSREF_PULSE_CNT register
starts sending the number of pulses.
3
1
2
1
SYSREF operational,
SYSREF divider as
required for training frame for non-JESD converters such as LM97600.
size.
Allows precise SYNC for n-bit frame training patterns
Re-clocked SYNC
When the SYNC pin is asserted, continuous SYSERF
External SYSREF
request
SYSREF_REQ_EN = 1
Pulser powered up
pulses occur. Turning on and off of the pulses is
synchronized, to prevent runt pulses from occurring
on SYSREF.
0
2
3
SYSREF_PD = 0
SYSREF_DDLY_PD = 0
Continuous SYSREF signal. Useful for validating
phase alignment of SYSREF clocks, but not
recommended for use in low-noise applications due to
crosstalk spurs.
Continuous
SYSREF
X
SYSREF_PLSR_PD = 1
(1)
(1) SDCLKoutY_PD = 0 as required per SYSREF output. This applies to any SYNC or SYSREF output on SDCLKoutY when
SDCLKoutY_MUX = 1 (SYSREF output)
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Feature Description (continued)
Table 1. Some Possible SYNC Configurations (continued)
NAME
SYNC_MODE
SYSREF_MUX
OTHER
DESCRIPTION
CLKin0_OUT_MUX = 0
SDCLKoutY_DDLY = 0
(Local sysref DDLY
bypassed)
SYSREF_DDLY_PD = 1
SYSREF_PLSR_PD = 1
SYSREF_PD = 1.
Direct SYSREF
distribution
A direct fan-out of SYSREF with no re-clocking to
clock distribution path.
0
0
9.3.2 JEDEC JESD204B
9.3.2.1 How To Enable SYSREF
Table 2 summarizes the bits needed to make SYSREF functionality operational.
Table 2. SYSREF Bits
REGIS
TER
FIELD
VALUE
DESCRIPTION
Must be clear to power-up SYSREF circuitry.
0x140
SYSREF_PD
0
0
1
SYSREF_DDLY_
PD
0x140
0x143
Must be clear to power-up digital delay circuitry during initial SYNC, to ensure deterministic timing.
Must be set to enable SYNC.
SYNC_EN
Do not hold local SYSREF_DDLY block in reset except at start.
Anytime SYSREF_PD = 1 because of user programming or device RESET, it is necessary to set
SYSREF_CLR for 15 clock distribution path cycles to clear the local SYSREF digital delay. After
clearing local delays, SYSREF_CLR must be cleared to allow SYSREF to operate.
0x143
SYSREF_CLR
1 → 0
Enabling JESD204B operation involves synchronizing all the clock dividers with the SYSREF divider, then
configuring the actual SYSREF functionality.
9.3.2.1.1 Setup of SYSREF Example
The following procedure is a programming example for a system operating with a 3000-MHz VCO frequency.
Use DCLKout0 and DCLKout2 to drive converters at 1500 MHz. Use DCLKout4 to drive an FPGA at 150 MHz.
Synchronize the converters and FPGA using two SYSREF pulses at 10 MHz.
1. Program registers 0x000 to 0x1fff as desired. Key to prepare for SYSREF operations (see Recommended
Programming Sequence):
a. Prepare for manual SYNC: SYNC_POL = 0, SYNC_MODE = 1, SYSREF_MUX = 0
b. Setup output dividers as per example: DCLKout0_DIV and DCLKout2_DIV = 2 for frequency of 1500
MHz. DCLKout4_DIV = 20 for frequency of 150 MHz.
c. Setup output dividers as per example: SYSREF_DIV = 300 for 10 MHz SYSREF
d. Setup SYSREF: SYSREF_PD
=
0, SYSREF_DDLY_PD
=
0, DCLKout0_DDLY_PD
=
0,
DCLKout2_DDLY_PD = 0, DCLKout4_DDLY_PD = 0, SYNC_EN = 1, SYSREF_PLSR_PD = 0,
SYSREF_PULSE_CNT = 1 (2 pulses). SDCLKout1_PD = 0, SDCLKout3_PD = 0
e. Clear Local SYSREF DDLY: SYSREF_CLR = 1.
2. Establish deterministic phase relationships between SYSREF and the device clock for JESD204B:
a. Set device clock and SYSREF divider digital delays: DCLKout0_DDLY_CNTH, DCLKout0_DDLY_CNTL,
DCLKout2_DDLY_CNTH, DCLKout2_DDLY_CNTL, DCLKout4_DDLY_CNTH, DCLKout4_DDLY_CNTL,
SYSREF_DDLY.
b. Set device clock digital delay half steps: DCLKout0_HS, DCLKout2_HS, DCLKout4_HS.
c. Set SYSREF clock digital delay as required to achieve known phase relationships: SDCLKout1_DDLY,
SDCLKout3_DDLY, SDCLKout5_DDLY.
d. To allow SYNC to effect dividers: SYNC_DIS0
SYNC_DISSYSREF = 0
= 0, SYNC_DIS2 = 0, SYNC_DIS4 = 0,
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e. Perform SYNC by toggling SYNC_POL = 1, then SYNC_POL = 0.
3. When the dividers are synchronized, disable SYNC from resetting these dividers. It is not desired for
SYSREF to reset it's own divider or the dividers of the output clocks.
a. Prevent SYSREF from affecting dividers: SYNC_DIS0 = 1, SYNC_DIS2 = 1, SYNC_DIS4 = 1,
SYNC_DISSYSREF = 1.
4. Release reset of local SYSREF digital delay.
a. SYSREF_CLR = 0. Note this bit needs to be set for only 15 clock distribution path cycles after
SYSREF_PD = 0.
5. Set SYSREF operation.
a. Allow pin SYNC event to start pulser: SYNC_MODE = 2.
b. Select pulser as SYSREF signal: SYSREF_MUX = 2.
6. After the procedure is complete, asserting the SYNC pin or toggling SYNC_POL results in a series of 2
SYSREF pulses.
9.3.2.1.2 SYSREF_CLR
The local digital delay of the SDCLKout is implemented as a shift buffer. To ensure no unwanted pulses occur at
this SYSREF output at startup when using SYSREF, clear the buffers by setting SYSREF_CLR = 1 for 15 VCO
clock cycles. This bit is set after a reset; thus, it must be cleared before the SYSREF output is used.
9.3.2.2 SYSREF Modes
9.3.2.2.1 SYSREF Pulser
This mode allows for the output of 1, 2, 4, or 8 SYSREF pulses for every SYNC pin event or SPI programming.
This implements the gapped periodic functionality of the JEDEC JESD204B specification.
When in SYSREF pulser mode, programming the field SYSREF_PULSE_CNT in register 0x13E results in the
pulser sending the programmed number of pulses.
9.3.2.2.2 Continuous SYSREF
This mode allows for continuous output of the SYSREF clock.
Continuous operation of SYSREF is not recommended, due to crosstalk from the SYSREF clock to device clock.
JESD204B is designed to operate with a single burst of pulses to initialize the system at startup, after which it is
theoretically not required to send another SYSREF, because the system continues to operate with deterministic
phases.
If continuous operation of SYSREF is required, consider using a SYSREF output from a non-adjacent output or
SYSREF from the OSCout pin, to minimize crosstalk.
9.3.2.2.3 SYSREF Request
This mode allows an external source to synchronously turn on or off a continuous stream of SYSREF pulses,
using the SYNC/SYSREF_REQ pin.
Set up the mode by programming SYSREF_REQ_EN = 1 and SYSREF_MUX = 2 (Pulser). The pulser does not
need to be powered for this mode of operation.
When the SYSREF_REQ pin is asserted, the SYSREF_MUX is synchronously set to continuous mode, providing
continuous pulses at the SYSREF frequency, until the SYSREF_REQ pin is unasserted and the final SYSREF
pulse completes sending synchronously.
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9.3.3 Digital Delay
Digital (coarse) delay allows a group of outputs to be delayed by 4 to 32 VCO cycles. The delay step can be as
small as half the period of the VCO cycle, by using the DCLKoutX_HS bit. There are two ways to use the digital
delay:
1. Fixed digital delay
2. Dynamic digital delay
In both delay modes, the regular clock divider is substituted with an alternative divide value. The substitute divide
value consists of two values, DCLKoutX_DDLY_CNTH and DCLKoutX_DDLY_CNTL. The minimum
_CNTH/_CNTL value is 2 and the maximum _CNTH/_CNTL value is 16. This results in a minimum alternative
divide value of 4 and a maximum of 32.
9.3.3.1 Fixed Digital Delay
Fixed digital delay value takes effect on the clock outputs after a SYNC event. As such, the outputs are LOW for
a while during the SYNC event. Applications that cannot accept clock interruption when adjusting digital delay
should use dynamic digital delay.
9.3.3.1.1 Fixed Digital Delay Example
Assuming the device already has the following initial configurations, and the application should delay DCLKout2
by one VCO cycle compared to DCLKout0:
•
•
•
VCO frequency = 2949.12 MHz
DCLKout0 = 368.64 MHz (DCLKout0_DIV = 8)
DCLKout2 = 368.64 MHz (DCLKout2_DIV = 8)
These steps should be followed:
1. Set DCLKout0_DDLY_CNTH = 4 and DCLKout2_DDLY_CNTH = 4. First part of delay for each clock.
2. Set DCLKout0_DDLY_CNTL = 4 and DCLKout2_DDLY_CNTL = 5. Second part of delay for each clock.
3. Set DCLKout0_DDLY_PD = 0 and DCLKout2_DDLY_PD = 0. Power up the digital delay circuit.
4. Set SYNC_DIS0 = 0 and SYNC_DIS2 = 0. Allow the output to be synchronized.
5. Perform SYNC by asserting, then deasserting SYNC. Either by using SYNC_POL bit or the SYNC pin.
6. When the SYNC is complete, power down DCLKout0_DDLY_PD = 1 and/or DCLKout2_DDLY_PD = 1 to
save power.
7. Set SYNC_DIS0 = 1 and SYNC_DIS2 = 1, to prevent the outputs from being synchronized by other
SYNC/SYSREF events.
No CLKout during SYNC
DCLKout0
368.64 MHz
DCLKout2
368.64 MHz
SYNC event
1 VCO cycle delay
Figure 14. Fixed Digital Delay Example
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9.3.3.2 Dynamic Digital Delay
Dynamic digital delay allows the phase of clocks to be changed with respect to each other, with little impact to
the clock signal. This is accomplished by substituting the regular clock divider with an alternate divide value for
one cycle. This substitution occurs
a number of times equal to the value programmed into the
DDLYd_STEP_CNT field for all outputs with DDLYdX_EN = 1.
•
•
By programming a larger alternate divider (delay) value, the phase of the adjusted outputs is delayed with
respect to the other clocks.
By programming a smaller alternate divider (delay) value, the phase of the adjusted output is advanced with
respect to the other clocks.
Table 3 shows the recommended DCLKoutX_DDLY_CNTH and DCLKoutX_DDLY_CNTL alternate divide setting
for delay by one VCO cycle. The clock output is high during the DCLKoutX_DDLY_CNTH time to permit a
continuous output clock. The clock output is low during the DCLKoutX_DDLY_CNTL time.
Table 3. Recommended DCLKoutX_DDLY_CNTH/_CNTL Values for Delay by One VCO Cycle
CLOCK DIVIDER
_CNTH
_CNTL
CLOCK DIVIDER
_CNTH
9
_CNTL
9
2
3
2
3
2
3
3
4
4
5
5
6
6
7
7
8
8
3
4
3
3
4
4
5
5
6
6
7
7
8
8
9
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
9
10
4
10
10
11
11
12
12
13
13
14
14
15
15
0(1)
10
5
11
6
11
7
12
8
12
9
13
10
11
12
13
14
15
16
13
14
14
15
15
0(1)
0(1)
(1) To achieve _CNTH/_CNTL value of 16, 0 must be programmed into the _CNTH/_CNTL field.
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9.3.3.3 Single and Multiple Dynamic Digital Delay Example
In this example, two separate adjustments are made to the device clocks. In the first adjustment, a single delay
of 1 VCO cycle occurs between DCLKout2 and DCLKout0. In the second adjustment, two delays of 1 VCO cycle
occur between DCLKout2 and DCLKout0. At this point in the example, DCLKout2 is delayed 3 VCO cycles
behind DCLKout0.
Assuming the device already has the following initial configurations:
•
•
•
VCO frequency: 2949.12 MHz
DCLKout0 = 368.64 MHz, DCLKout0_DIV = 8
DCLKout2 = 368.64 MHz, DCLKout2_DIV = 8
The following steps illustrate the example above:
1. Set DCLKout2_DDLY_CNTH = 4. First part of delay for DCLKout2.
2. Set DCLKout2_DDLY_CNTL = 5. Second part of delay for DCLKout2.
3. Set DCLKout2_DDLY_PD = 0. Enable the digital delay for DCLKout2.
4. Set DDLYd2_EN = 1. Enable dynamic digital delay for DCLKout2.
5. Set SYNC_DIS0 = 1 and SYNC_DIS2 = 0. Sync should be disabled to DCLKout0, but not DCLKout2.
6. Set SYNC_MODE = 3. Enable SYNC event from SPI write to the DDLYd_STEP_CNT register.
7. Set SYNC_MODE = 2, SYSREF_MUX = 2. Setup proper SYNC settings.
8. Set DDLYd_STEP_CNT = 1. This begins the first adjustment.
Before step 8 DCLKout2 clock edge is aligned with DCLKout0.
After step 8, DCLKout2 counts four VCO cycles high and then five VCO cycles low as programmed by
DCLKout2_DDLY_CNTH and DCLKout2_DDLY_CNTL fields, effectively delaying DCLKout2 by one VCO
cycle with respect to DCLKout0. This is the first adjustment.
9. Set DDLYd_STEP_CNT = 2. This begins the second adjustment.
Before step 9, DCLKout2 clock edge was delayed 1 VCO cycle from DCLKout0.
After step 9, DCLKout2 counts four VCO cycles high and then five VCO cycles low, as programmed by
DCLKout2_DDLY_CNTH and DCLKout2_DDLY_CNTL fields twice, delaying DCLKout2 by two VCO cycles
with respect to DCLKout0. This is the second adjustment.
VCO
2949.12 MHz
DCLKout0
368.64 MHz
DCLKout2
368.64 MHz
First
Adjustment
CNTH = 4 CNTL = 5
DCLKout2
368.64 MHz
Second
Adjustment
CNTH = 4 CNTL = 5
CNTH = 4 CNTL = 5
Figure 15. Single and Multiple Adjustment Dynamic Digital Delay Example
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9.3.4 SYSREF to Device Clock Alignment
To ensure proper JESD204B operation, the timing relationship between the SYSREF and the device clock must
be adjusted for optimum setup and hold time as shown in
Added timing alignment figure, alignment equations to SYSREF to Device Clock Alignment . The global SYSREF
digital delay (SYSREF_DDLY). local SYSREF digital delay (SDCLKoutY_DDLY), local SYSREF half step
(SDCLKoutY_HS), and local SYSREF analog delay (SDCLKoutY_ADLY, SDCLKoutY_ADLY_EN) can be
adjusted to provide the required setup and hold time between SYSREF and device clock. It is also possible to
adjust the device clock digital delay (DCLKoutX_DDLY_CNTH, DCLKoutX_DDLY_CNTL), device clock half step
(DCLKoutX_HS), device clock analog delay (DCLKoutX_ADLY, DCLKoutX_ADLY_EN), and device clock muxes
(DCLKoutX_MUX, DCLKoutX_ADLY_MUX) to adjust phase with respect to SYSREF.
Figure 16. SYSREF to Device Clock Timing Alignment
Depending on the settings for DCLKoutX and the SYSREF divider, some adjustment may be needed to correctly
align DCLKoutX to SDCLKoutY. Equation 1 and Equation 2 predict the relative DCLKoutX to SDCLKoutY delay:
DELAYDCLK = DCLKoutX_DDLY_CNTH + DCLKoutX_DDLY_CNTL
(1)
DELAYSDCLK = SYSREF_DDLY + SDCLKoutY_DDLY + SYSREF_DIV_ADJUST + DCLKout_MUX_ADJUST
where
•
•
SYSREF_DIV_ADJUST = 2 IF (SYSREF_DIV % 4 < 2) ELSE 3
DCLKoutX_MUX_ADJUST = 1 IF (Duty Cycle Correction enabled) ELSE 0
(2)
For the relative delay equations, the cycle delay rather than the register value should be used, since cycle delay
does not always equal register value (example: _CNTH/_CNTL=0, delay=16). Device clock duty cycle correction
can be enabled for both digital and analog paths, either by setting DCLKoutX_MUX=1 (digital only), or by setting
DCLKoutX_MUX=3 and DCLKoutX_ADLY_MUX=1. If half step is enabled on either path, delay can be included
by subtracting 0.5 from the enabled path. As an example, if DCLKoutX_DDLY_CNTH=7,
DCLKoutX_DDLY_CNTL=6,
SYSREF_DDLY=8,
SDCLKoutY_DDLY=2
cycles,
SYSREF_DIV=30,
DCLKoutX_MUX=1, DCLKoutX_HS=0, SDCLKoutX_HS=0:
•
•
•
•
DELAYDCLK = 7 + 6 = 13
SYSREF_DIV_ADJUST = (30 % 4 < 2) ? 2 : 3 = 3
DCLKoutX_MUX_ADJUST = DCC ? 1 : 0 = 0
DELAYSDCLK = 8 + 2 + 3 + 0 = 13
To calculate the expected time delay from the first edge of DCLKoutX to the first edge of SDCLKoutY, refer to
Equation 3. Substitute the analog delays with the appropriate time values (in seconds) according to
DCLKoutX_ADLY, DCLKoutX_ADLY_MUX, DCLKout_MUX and SDCLKoutY_ADLY_EN, SDCLKoutY_ADLY.
tsJESD204B is provided in the Electrical Characteristics section for the conditions in the example above as -80 ps.
tDCLK-to-SDCLK = (FDistribution
)
-1 × (DELAYSDCLK - DELAYDCLK) + SDCLKoutY_ADLY - DCLKoutY_ADLY + tsJESD204B
(3)
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9.3.5 Input Clock Switching
Manual, pin select, and automatic are three kinds clock input switching modes that can be set with the
CLKin_SEL_MODE register.
The following sections describe how the active input clock is selected and what causes a switching event in the
various clock input selection modes.
9.3.5.1 Input Clock Switching - Manual Mode
When CLKin_SEL_MODE is 0, 1, or 2, then CLKin0, CLKin1, or CLKin2 respectively is always selected as the
active input clock. Manual mode also overrides the EN_CLKinX bits, such that the CLKinX buffer operates even if
EN_CLKinX = 0.
If holdover is entered in this mode, the device re-locks to the selected CLKin upon holdover exit.
9.3.5.2 Input Clock Switching - Pin Select Mode
When CLKin_SEL_MODE is 3, the pins CLKin_SEL0 and CLKin_SEL1 select which clock input is active.
Configuring Pin Select Mode
The CLKin_SEL0_TYPE must be programmed to an input value for the CLKin_SEL0 pin to function as an input
for pin select mode.
The CLKin_SEL1_TYPE must be programmed to an input value for the CLKin_SEL1 pin to function as an input
for pin select mode.
If the CLKin_SELX_TYPE is set as output, the pin input value is considered low.
The polarity of CLKin_SEL0 and CLKin_SEL1 input pins can be inverted with the CLKin_SEL_INV bit.
Table 4 defines which input clock is active depending on CLKin_SEL0 and CLKin_SEL1 state.
Table 4. Active Clock Input - Pin Select Mode, CLKin_SEL_INV = 0
PIN CLKin_SEL1
PIN CLKin_SEL0
ACTIVE CLOCK
CLKin0
Low
Low
High
High
Low
High
Low
High
CLKin1
CLKin2
Holdover
The pin select mode ignores the EN_CLKinX bits, such that the CLKinX buffer operates even if EN_CLKinX = 0.
To switch as fast as possible, keep the switchable clock input buffers enabled (EN_CLKinX = 1).
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9.3.5.3 Input Clock Switching - Automatic Mode
When CLKin_SEL_MODE is 4 and LOS_EN = 1, the active clock is selected in round-robin order of enabled
clock inputs, starting on an input clock switch event. The switching order of the clocks is CLKin0 → CLKin1 →
CLKin2 → CLKin0, and so forth.
For a clock input to be eligible to be switched through, it must be enabled using EN_CLKinX. The
LOS_TIMEOUT should also be set to a frequency below the input frequency.
To ensure LOS is valid for AC-coupled inputs, the MOS mode must be set for CLKinX and no termination is
allowed to be between the pins unless DC-blocked. For example, with an LVDS differential signal into CLKin0, no
100-Ω termination should be placed directly across CLKin0 and CLKin0* pins on the IC side of the AC coupling
capacitors. 100 Ω could instead be placed on the transmitter side of the AC coupling capacitors.
Starting Active Clock
When programming this mode, the currently active clock remains active if PLL1 lock detect is high. To ensure a
particular clock input is the active clock when starting this mode, program CLKin_SEL_MODE to the manual
mode which selects the desired clock input (CLKin0, 1, or 2). Wait for PLL1 to lock PLL1_DLD = 1, then select
this mode with CLKin_SEL_MODE = 4.
9.3.6 Digital Lock Detect
Both PLL1 and PLL2 support digital lock detect. Digital lock detect compares the phase between the reference
path (R) and the feedback path (N) of the PLL at the phase detector. When the time error(phase error) between
the two signals is less than a specified window size (ε), a lock detect count increments. When the lock detect
count reaches a user-specified value, PLL1_DLD_CNT or PLL2_DLD_CNT, lock detect is asserted (true). When
digital lock detect is true, a single phase comparison outside the specified window causes digital lock detect to
be deasserted (false). This is illustrated in Figure 17 .
NO
NO
PLLX
Lock Detected = False
Lock Count = 0
YES
YES
Increment
PLLX Lock Count
PLLX
Lock Detected = True
PLLX Lock Count =
PLLX_DLD_CNT
START
Phase Error < g
Phase Error < g
YES
NO
Figure 17. Digital Lock Detect Flowchart
This incremental lock detect count feature functions as a digital filter, to ensure that lock detect is not asserted
when the phases of R and N are within the specified tolerance for a brief time during initial phase lock.
See Digital Lock Detect Frequency Accuracy for more detailed information on programming the registers to
achieve a specified frequency accuracy in ppm with lock detect.
The digital lock detect signal can be monitored on the Status_LD1 or Status_LD2 pin. The pin may be
programmed to output the status of lock detect for PLL1, PLL2, or both PLL1 and PLL2.
The digital lock detect feature can also be used with holdover to automatically exit holdover mode. See Exiting
Holdover for more info.
NOTE
In cases where the period of the phase detector frequency approaches the value of the
default PLL1_WND_SIZE increment (40 ns), the lock detect circuit will not function with
the default value of PLL1_WND_SIZE. For PLL1 phase detector frequencies at or above
25 MHz, TI recommends setting PLL1_WND_SIZE less than or equal to 0x02 (19 ns).
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9.3.7 Holdover
Holdover mode causes PLL2 to stay locked on frequency with minimal frequency drift when an input clock
reference to PLL1 becomes invalid, when PLL1 loses lock, or when the CPout1 voltage is outside of a user-
specified acceptable range. While in holdover mode, the PLL1 charge pump is TRI-STATED and a fixed tuning
voltage is set on CPout1 to operate PLL1 in open loop.
9.3.7.1 Enable Holdover
Program HOLDOVER_EN = 1 to enable holdover mode. Enabling holdover mode does not place the device in
holdover unless the relevant criteria have been met (example: PLL1 loss of lock). Program HOLDOVER_FORCE
= 1 to force the device into holdover.
Holdover mode can be configured to set the CPout1 voltage upon holdover entry, to a fixed user-defined voltage
or a tracked voltage.
9.3.7.1.1 Fixed (Manual) CPout1 Holdover Mode
By programming MAN_DAC_EN = 1, the MAN_DAC value is set on the CPout1 pin during holdover.
The user can optionally enable CPout1 voltage tracking (TRACK_EN = 1), read back the tracked DAC value,
then reprogram MAN_DAC value to a user-desired value based on information from previous DAC read backs.
This allows the most user control over the holdover CPout1 voltage, but also requires more user intervention.
9.3.7.1.2 Tracked CPout1 Holdover Mode
By programming MAN_DAC_EN = 0 and TRACK_EN = 1, the tracked voltage of CPout1 is set on the CPout1
pin during holdover. When the DAC has acquired the current CPout1 voltage, the DAC_Locked signal is set,
which may be observed on Status_LD1 or Status_LD2 pins by programming PLL1_LD_MUX or PLL2_LD_MUX,
respectively.
Updates to the DAC value for the Tracked CPout1 sub-mode occurs at the rate of the PLL1 phase detector
frequency divided by (DAC_CLK_MULT × DAC_CLK_CNTR).
The DAC update rate should be programmed for ≤ 100 kHz to ensure DAC holdover accuracy.
The ability to program slow DAC update rates, for example one DAC update per 4.08 seconds when using 1024-
kHz PLL1 phase-detector frequency with DAC_CLK_MULT = 16,384 and DAC_CLK_CNTR = 255, allows the
device to look-back and set CPout1 at previous "good" CPout1 tuning voltage values before the event which
caused holdover to occur.
The current voltage of DAC value can be read back using RB_DAC_VALUE; see RB_DAC_VALUE.
9.3.7.2 Entering Holdover
There are several ways to enter holdover.
•
•
•
HOLDOVER_LOS_DET = 1 and a loss of active reference is detected.
HOLDOVER_PLL1_DET = 1 and PLL1 loss of lock is detected.
HOLDOVER_VTUNE_DET = 1 and the voltage monitored by the DAC on CPout1 is less than the value set
by DAC_TRIP_LOW, or greater than the value set by DAC_TRIP_HIGH.
•
HOLDOVER_FORCE = 1.
9.3.7.3 During Holdover
PLL1 is run in open-loop mode.
•
•
•
•
•
PLL1 charge pump is set to TRI-STATE.
PLL1 DLD is deasserted.
The HOLDOVER status is asserted.
During holdover, if PLL2 was locked prior to entry of holdover mode, PLL2 DLD continues to be asserted.
CPout1 voltage is set to:
–
–
a voltage set in the MAN_DAC register (MAN_DAC_EN = 1).
a voltage determined to be the last valid CPout1 voltage (MAN_DAC_EN = 0).
•
PLL1 attempts to lock with the active clock input.
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The HOLDOVER status signal can be monitored on the Status_LD1 or Status_LD2 pin by programming the
PLL1_DLD_MUX or PLL2_DLD_MUX register to Holdover Status.
9.3.7.4 Exiting Holdover
Holdover mode can be exited in one of two ways.
•
•
Manually, by programming the device from the host.
Automatically, by a clock operating within a specified ppm of the current PLL1 frequency on the active clock
input.
9.3.7.5 Holdover Frequency Accuracy and DAC Performance
When in holdover mode, PLL1 runs in open loop and the DAC sets the CPout1 voltage. If fixed CPout1 mode is
used, then the output of the DAC is voltage-dependant upon the MAN_DAC register. If tracked CPout1 mode is
used, then the output of the DAC is the voltage at the CPout1 pin before holdover mode was entered. When
using tracked mode and MAN_DAC_EN = 1, during holdover the DAC value is loaded with the programmed
value in MAN_DAC, not the tracked value.
When in tracked CPout1 mode, the DAC has a worst-case tracking error of ±2 LSBs when PLL1 tuning voltage is
acquired. The step size is approximately 3.2 mV, thus the VCXO frequency error during holdover mode caused
by the DAC tracking accuracy is ±6.4 mV × Kv, where Kv is the tuning sensitivity of the VCXO in use. Thus, the
accuracy of the system when in holdover mode in ppm is:
6.4 mV × Kv × 1e6
Holdover accuracy (ppm) =
VCXO Frequency
(4)
Example: consider a system with a 19.2-MHz clock input, and a 153.6-MHz VCXO with a Kv of 17 kHz/V. The
accuracy of the system in holdover in ppm is:
±0.71 ppm = ±6.4 mV × 17 kHz/V × 1e6 / 153.6 MHz
(5)
It is important to account for this frequency error when determining the allowable frequency error window to
cause holdover mode to exit.
9.3.7.6 Holdover Mode - Automatic Exit of Holdover
The LMK0482x device can be programmed to automatically exit holdover mode when the frequency on the
active clock input achieves a specified accuracy. The programmable variables include PLL1_WND_SIZE and
HOLDOVER_DLD_CNT.
See Digital Lock Detect Frequency Accuracy to calculate the register values to cause holdover to automatically
exit upon reference signal recovery to within a user specified ppm error of the holdover frequency.
The time to exit holdover may vary, because the condition for automatic holdover exit is for the reference and
feedback signals to have a time/phase error less than a programmable value. Because two clock signals may be
very close in frequency but not close in phase, it may take a long time for the phases of the clocks to align
themselves within the allowable time/phase error before holdover exits.
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9.4 Device Functional Modes
The following section describes the settings to enable various modes of operation for the LMK0482x family. See
Figure 12 and Figure 13 for visual diagrams of each mode.
The LMK0482x family is a flexible device that can be configured for many different use cases. The following
simplified block diagrams show the user the different use cases of the device.
9.4.1 Dual PLL
Figure 18 illustrates the typical use case of the LMK0482x family in dual-loop mode. In dual-loop mode, the
reference to PLL1 is from CLKin0, CLKin1, or CLKin2. An external VCXO or tunable crystal is used to provide
feedback for the first PLL, and a reference to the second PLL. This first PLL cleans the jitter with the VCXO or
low-cost tunable crystal by using a narrow loop bandwidth. The VCXO or tunable crystal output may be buffered
through the OSCout port. The VCXO or tunable crystal is used as the reference to PLL2, and may be doubled
using the frequency doubler. The internal VCO drives up to seven divide/delay blocks, which drive up to 14 clock
outputs.
Hitless switching and holdover functionality are optionally available when the input reference clock is lost.
Holdover works by fixing the tuning voltage of PLL1 to the VCXO or tunable crystal.
It is also possible to use an external VCO in place of the PLL2 internal VCO. In this case, one less CLKin is
available as a reference.
LMK04821 includes VCO1 divider on VCO1 output.
PLL1
PLL2
Up to 1 OSCout
External
Loop Filter
OSCout
External VCXO
or Tunable
Crystal
OSCout*
CLKinX
CLKinX*
Up to 3
inputs
R
N
7 Device
Clocks
DCLKoutX
7 blocks
Phase
Detector
PLL1
CPout2
External
Loop Filter
R
Device Clock
Divider
Digital Delay
Analog Delay
Phase
Detector
PLL2
Partially
Integrated
Loop Filter
DCLKoutX*
Input
Buffer
N
Dual
Internal
VCOs
7 SYSREF
or Device
Clocks
SYSREF
Digital Delay
Analog Delay
SDCLKoutY
SDCLKoutY*
LMK0482x
1 Global SYSREF Divider
Figure 18. Simplified Functional Block Diagram for Dual-Loop Mode
Table 5. Dual-Loop Mode Register Configuration
REGISTER
ADDRESS
FIELD
FUNCTION
VALUE
SELECTED VALUE
PLL1_NCLK_MUX
PLL2_NCLK_MUX
FB_MUX_EN
FB_MUX
0x13F
Selects the input to the PLL1 N divider
Selects the input to the PLL2 N divider
Enables the feedback mux
0
0
0
X
0
OSCin
PLL2_P
Disabled
0x13F
0x13F
0x13F
Selects the output of the feedback mux
Powers down the OSCin port
Don't care because FB_MUX is disabled
Powered up
OSCin_PD
0x140
Selects where the output of CLKin0 is
directed.
CLKin0_OUT_MUX
0x147
2
PLL1
Selects where the output of CLKin1 is
directed.
CLKin1_OUT_MUX
VCO_MUX
0x147
0x138
2
PLL1
Selects the VCO 0, 1 or an external VCO
0 or 1
VCO 0 or VCO 1
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9.4.2 Zero-Delay Dual PLL
Figure 19 illustrates the use case of cascaded zero-delay dual-loop mode. This configuration differs from dual-
loop mode Figure 18 in that the feedback for PLL2 is driven by a clock output instead of the VCO output.
Figure 20 illustrates the use case of nested zero-delay dual-loop mode. This configuration is similar to the dual
PLL in Dual PLL, except that the feedback to the first PLL is driven by a clock output. This causes the clock
outputs to have deterministic phase relationship with the clock input. Because all the clock outputs can be
synchronized together, all the clock outputs can share the same deterministic phase relationship with the clock
input signal. The feedback to PLL1 can be connected internally as shown using CLKout6, CLKout8, SYSREF, or
externally using FBCLKin (CLKin1).
It is also possible to use an external VCO in place of the PLL2 internal VCO; however, because CLKin1 must be
used as Fin for the external VCO, it is unavailable as a reference to PLL1 or as external zero-delay feedback.
LMK04821 includes VCO1 divider on VCO1 output.
PLL1
PLL2
Up to 1 OSCout
External
Loop Filter
OSCout
External VCXO
or Tunable
Crystal
OSCout*
CLKinX
CLKinX*
R
N
Phase
Detector
PLL1
CPout2
External
Loop Filter
Up to 3
inputs
Divider
Digital Delay
Analog Delay
SDCLKoutY
R
Phase
Detector
PLL2
Partially
Integrated
Loop Filter
SDCLKoutY*
7 SYSREF
or Device
Clocks
Input
Buffer
N
Dual
Internal
VCOs
7 blocks
SYSREF
Analog Delay
Digital Delay
DCLKoutX
DCLKoutX*
7 Device
Clocks
Internal or external loopback, user programmable
1 Global SYSREF Divider
LMK0482x
Figure 19. Simplified Functional Block Diagram for Cascaded Zero-Delay Dual-Loop Mode
Table 6. Cascaded Zero-Delay Dual-Loop Mode Register Configuration
REGISTER
ADDRESS
FIELD
FUNCTION
VALUE
SELECTED VALUE
PLL1_NCLK_MUX
PLL2_NCLK_MUX
FB_MUX_EN
0x13F
Selects the input to the PLL1 N divider
Selects the input to the PLL2 N divider
Enables the feedback mux.
0
1
1
OSCin
0x13F
Feedback mux
0x13F
Feedback mux enabled
Select between DCLKout6,
DCLKout8, SYSREF
FB_MUX
0x13F
Selects the output of the feedback mux.
0, 1, or 2
OSCin_PD
CLKin0_OUT_MUX
CLKin1_OUT_MUX
VCO_MUX
0x140
0x147
0x147
0x138
Powers down the OSCin port.
0
Powered up
PLL1
Selects where the output of CLKin0 is directed.
Selects where the output of CLKin1 is directed.
Selects the VCO 0, 1 or an external VCO
0
0 or 2
0 or 1
Fin or PLL1
VCO 0 or VCO 1
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PLL1
PLL2
Up to 1 OSCout
External
Loop Filter
OSCout
External VCXO
or Tunable
Crystal
OSCout*
CLKinX
R
CLKinX*
Phase
CPout2
External
Loop Filter
Up to 3
inputs
Detector
PLL1
Divider
Digital Delay
Analog Delay
SDCLKoutY
R
Phase
Detector
PLL2
Partially
Integrated
Loop Filter
SDCLKoutY*
7 SYSREF
or Device
Clocks
N
Input
Buffer
N
Dual
Internal
VCOs
7 blocks
SYSREF
Analog Delay
Digital Delay
DCLKoutX
DCLKoutX*
7 Device
Clocks
Internal or external loopback, user programmable
1 Global SYSREF Divider
LMK0482x
Figure 20. Simplified Functional Block Diagram for Nested Zero-Delay Dual-Loop Mode
LMK04821 includes the VCO1 divider on the VCO1 output.
Table 7 illustrates nested zero-delay mode. This is the same as cascaded, except the clock out feedback is to
PLL1. The CLKin and CLKout have the same deterministic phase relationship, but the VCXO's phase is not
deterministic to the CLKin or CLKouts.
Table 7. Nested Zero-Delay Dual-Loop Mode Register Configuration
REGISTER
ADDRESS
FIELD
FUNCTION
VALUE
SELECTED VALUE
PLL1_NCLK_MUX
PLL2_NCLK_MUX
FB_MUX_EN
0x13F
Selects the input to the PLL1 N divider
Selects the input to the PLL2 N divider
Enables the feedback mux.
1
0
1
Feedback mux
PLL2 P
0x13F
0x13F
Enabled
Select between DCLKout6,
DCLKout8, SYSREF
FB_MUX
0x13F
Selects the output of the feedback mux.
0, 1, or 2
OSCin_PD
CLKin0_OUT_MUX
CLKin1_OUT_MUX
VCO_MUX
0x140
0x147
0x147
0x138
Powers down the OSCin port.
0
Powered up
PLL1
Selects where the output of CLKin0 is directed.
Selects where the output of CLKin1 is directed.
Selects the VCO 0, 1 or an external VCO
2
0 or 2
0 or 1
Fin or PLL1
VCO 0 or VCO 1
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9.4.3 Single-Loop Mode
Figure 21 illustrates the use case of PLL2 single loop mode. When used with a clean high frequency reference
on OSCin, performance can be comparable to (or even better than) dual-loop mode.
Figure 21. Simplified Functional Block Diagram for Single-Loop Mode
Table 8. Single-Loop Mode Register Configuration
REGISTER
ADDRESS
FIELD
FUNCTION
VALUE
SELECTED VALUE
PLL1_NCLK_MUX
PLL2_NCLK_MUX
FB_MUX_EN
0x13F
Selects the input to the PLL1 N divider
Selects the input to the PLL2 N divider
Enables the feedback mux.
X
0
0
Don't care
PLL2 P
0x13F
0x13F
Disabled
Select between DCLKout6, DCLKout8,
SYSREF
FB_MUX
0x13F
Selects the output of the feedback mux. 0, 1, or 2
OSCin_PD
PLL1_PD
0x140
0x140
Powers down the OSCin port.
Powers down PLL1.
0
1
Powered up
Powered down
Selects where the output of CLKin0 is
directed.
CLKin0_OUT_MUX
0x147
X
Don't care
Selects where the output of CLKin1 is
directed.
CLKin1_OUT_MUX
VCO_MUX
0x147
0x138
3
Off
Selects the VCO 0, 1 or an external VCO
0 or 1
VCO 0 or VCO 1
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9.4.4 Single-Loop Mode With External VCO
Adding an external VCO is possible using the CLKin1/Fin input port. The input may be single-ended or
differential. At high frequency the input impedance to Fin is low, so a resistive pad is recommended for matching.
Figure 22. Simplified Functional Block Diagram for Single-Loop Mode With External VCO
Table 9. Single-Loop Mode With External VCO Register Configuration
REGISTER
FIELD
FUNCTION
VALUE
SELECTED VALUE
ADDRESS
0x13F
0x13F
0x13F
0x13F
0x140
0x140
0x140
0x140
PLL1_NCLK_MUX
PLL2_NCLK_MUX
FB_MUX_EN
FB_MUX
Selects the input to the PLL1 N divider
Selects the input to the PLL2 N divider
Enables the feedback mux.
X
0
0
X
0
1
1
1
Don't care
PLL2_P
Disabled
Selects the output of the feedback mux.
Powers down the OSCin port.
Powers down the VCO LDO.
Powers down the VCO.
Don't care
OSCin_PD
Powered up
Powered down
Powered down
Powered down
VCO_LDO_PD
VCO_PD
PLL1_PD
Powers down PLL1.
Selects where the output of CLKin0 is
directed.
CLKin0_OUT_MUX
0x147
X
Don't care
Selects where the output of CLKin1 is
directed.
CLKin1_OUT_MUX
VCO_MUX
0x147
0x138
0
2
Fin
Selects the VCO 0, 1 or an external VCO
External VCO
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9.4.5 Distribution Mode
Figure 23 illustrates the use case of distribution mode. As in all other use cases, OSCin to OSCout can be used
as a buffer to OSCin or from clock distribution path via CLKout6, CLKout8, or the SYSREF divider. At high
frequency the input impedance to Fin is low, so a resistive pad is recommended for matching.
Figure 23. Simplified Functional Block Diagram for Distribution Mode
Table 10. Distribution Mode Register Configuration
REGISTER
FIELD
FUNCTION
VALUE
SELECTED VALUE
ADDRESS
0x13F
0x13F
0x13F
0x13F
0x140
0x140
0x140
0x140
0x173
0x173
PLL1_NCLK_MUX
PLL2_NCLK_MUX
FB_MUX_EN
FB_MUX
Selects the input to the PLL1 N divider
Selects the input to the PLL2 N divider
Enables the feedback mux.
Selects the output of the feedback mux.
Powers down the OSCin port.
Powers down the VCO LDO.
Powers down the VCO.
X
X
0
X
1
1
1
1
1
1
Don't care
Don't care
Disabled
Don't care
OSCin_PD
Powered down
Powered down
Powered down
Powered down
Powered down
Powered down
VCO_LDO_PD
VCO_PD
PLL1_PD
Powers down PLL1.
PLL2_PRE_PD
PLL2_PD
Powers down PLL2 prescaler.
Powers down PLL2.
Selects where the output of CLKin0 is
directed.
CLKin0_OUT_MUX
0x147
X
Don't care
Selects where the output of CLKin1 is
directed.
CLKin1_OUT_MUX
VCO_MUX
0x147
0x138
0
2
Fin
Selects the VCO 0, 1 or an external VCO
External VCO
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9.5 Programming
LMK0482x family devices are programmed using 24-bit registers. Each register consists of a 1-bit command field
(R/W), a 2-bit multi-byte field (W1, W0), a 13-bit address field (A12 to A0), and an 8-bit data field (D7 to D0). The
contents of each register is clocked in MSB first (R/W), and the LSB (D0) last. During programming, the CS*
signal is held low. The serial data is clocked in on the rising edge of the SCK signal. After the LSB is clocked in,
the CS* signal goes high to latch the contents into the shift register. TI recommends programming registers in
numeric order – for example, 0x000 to 0x1FFF – to achieve proper device operation. Each register consists of
one or more fields which control the device functionality. See Electrical Characteristics and Figure 1 for timing
details.
R/W bit = 0 is for SPI write. R/W bit = 1 is for SPI read.
W1 and W0 should be written as 0.
9.5.1 Recommended Programming Sequence
Registers are programmed in numeric order, with 0x000 being the first and 0x1FFF being the last register
programmed. The recommended programming sequence from POR involves:
1. Program register 0x000 with RESET = 1.
2. Program registers in numeric order from 0x000 to 0x165. Ensure the following register is programmed as
follows:
– 0x145 = 127 (0x7F)
3. Program register 0x171 to 0xAA and 0x172 to 0x02.
4. If using LMK04821, program register 0x174.
5. Program registers 0x17C and 0x17D as required by OPT_REG_1 and OPT_REG_2.
6. Program registers 0x166 to 0x1FFF.
When using LMK04821: Program register 0x174, bits 4:0 (VCO1_DIV) with the proper value before programming
the PLL2_N register in 0x166, 0x167, and 0x168 for proper total PLL2_N value.
Program register 0x171, 0x172, 0x17C (OPT_REG_1) and 0x17D (OPT_REG_2) before programming PLL2 in
registers: 0x166, 0x167, and 0x168, to optimize PLL2_N and VCO1 phase-noise performance over temperature.
9.5.1.1 SPI LOCK
When writing to SPI_LOCK, registers 0x1FFD, 0x1FFE, and 0x1FFF should all always be written sequentially.
9.5.1.2 SYSREF_CLR
When using SYSREF output, SYSREF local digital delay block should be cleared using SYSREF_CLR bit. See
SYSREF_CLR for more info.
9.5.1.3 RESET Pin
If the RESET pin is not used during normal operation, TI recommends programming the RESET_TYPE register
to an output setting, to prevent noise from spontaneously resetting the device.
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9.6 Register Maps
9.6.1 Register Map for Device Programming
Table 11 provides the register map for device programming. Any register can be read from the same data
address it is written to.
Table 11. LMK0482x Register Map
ADDRESS
[11:0]
DATA
7
6
5
4
3
2
1
0
SPI_3WIRE
_DIS
0x000
0x002
RESET
0
0
0
0
0
0
POWER
DOWN
0
0
0
0
0
0
0
0x003
0x004
0x005
0x006
0x00C
0x00D
ID_DEVICE_TYPE
ID_PROD[15:8]
ID_PROD[7:0]
ID_MASKREV
ID_VNDR[15:8]
ID_VNDR[7:0]
CLKout0_1
_ODL
CLKout0_1
_IDL
0x100
0x101
0x103
0
DCLKout0_DIV
DCLKout0_DDLY_CNTH
DCLKout0_ADLY
SDCLKout1
DCLKout0_DDLY_CNTL
DCLKout0_
DCLKout0_MUX
ADLY_MUX
SDCLKout1_DDLY
SDCLKout1_ADLY
SDCLKout1_DIS_MODE
CLKout0_FMT
DCLKout0
_HS
SDCLKout1
_HS
0x104
0x105
0x106
0x107
0
0
_MUX
SDCLKout1_
ADLY_EN
0
0
CLKout0_1
_PD
SDCLKout1
_PD
DCLKout0
_ DDLY_PD
DCLKout0
_ HSg_PD
DCLKout0
_ ADLYg_PD
DCLKout0
_ADLY _PD
SDCLKout1
_POL
DCLKout0
_POL
CLKout1_FMT
CLKout2_3
_ODL
CLKout2_3
_IDL
0x108
0x109
0x10B
0
DCLKout2_DIV
DCLKout2_DDLY_CNTH
DCLKout2_ADLY
SDCLKout3
DCLKout2_DDLY_CNTL
DCLKout2_
DCLKout2_MUX
ADLY_MUX
SDCLKout3_DDLY
SDCLKout3_ADLY
SDCLKout3_DIS_MODE
CLKout2_FMT
DCLKout2
_HS
SDCLKout3
_HS
0x10C
0x10D
0x10E
0x10F
0
0
_MUX
SDCLKout3
_ ADLY_EN
0
0
DCLKout2
_ DDLY_PD
DCLKout2
_ HSg_PD
DCLKout2
_ ADLYg_PD
DCLKout2
_ADLY _PD
CLKout2_3
_PD
SDCLKout3
_PD
SDCLKout3
_POL
DCLKout2
_POL
CLKout3_FMT
CLKout4_5
_ODL
CLKout4_5
_IDL
0x110
0x111
0x113
0
DCLKout4_DIV
DCLKout4_DDLY_CNTH
DCLKout4_ADLY
SDCLKout5
DCLKout4_DDLY_CNTL
DCLKout4_
DCLKout4_MUX
ADLY_MUX
SDCLKout5_DDLY
SDCLKout5_ADLY
SDCLKout5_DIS_MODE
CLKout4_FMT
DCLKout4
_HS
SDCLKout5
_HS
0x114
0x115
0x116
0x117
0x118
0
0
_MUX
SDCLKout5
_ ADLY_EN
0
0
DCLKout4
_ DDLY_PD
DCLKout4
_ HSg_PD
DCLKout4
_ ADLYg_PD
DCLKout4
_ADLY _PD
CLKout4_5
_PD
SDCLKout5
_PD
SDCLKout5
_POL
DCLKout4
_POL
CLKout5_FMT
CLKout6_7
_ODL
CLKout6_8
_IDL
0
DCLKout6_DIV
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Register Maps (continued)
Table 11. LMK0482x Register Map (continued)
ADDRESS
[11:0]
DATA
7
6
5
4
3
2
1
0
0x119
DCLKout6_DDLY_CNTH
DCLKout6_ADLY
SDCLKout7
DCLKout6_DDLY_CNTL
DCLKout6_
0x11B
0x11C
0x11D
0x11E
0x11F
DCLKout6_MUX
ADLY_MUX
SDCLKout7_DDLY
SDCLKout7_ADLY
SDCLKout7_DIS_MODE
CLKout6_FMT
DCLKout6
_HS
SDCLKout7
_HS
0
0
_MUX
SDCLKout7
_ ADLY_EN
0
0
DCLKout6
_ DDLY_PD
DCLKout6
_ HSg_PD
DCLKout6
_ ADLYg_PD
DCLKout6
_ADLY _PD
CLKout6_7
_PD
SDCLKout7
_PD
SDCLKout7
_POL
CLKout7
_FMT
DCLKout6
_POL
CLKout8_9
_ODL
CLKout8_9
_IDL
0x120
0x121
0x123
0
DCLKout8_DIV
DCLKout8_DDLY_CNTH
DCLKout8_ADLY
SDCLKout9
DCLKout8_DDLY_CNTL
DCLKout8
DCLKout8_MUX
_ ADLY_MUX
SDCLKout9_DDLY
SDCLKout9_ADLY
SDCLKout9_DIS_MODE
CLKout8_FMT
DCLKout8
_HS
SDCLKout9
_HS
0x124
0x125
0x126
0x127
0
0
_MUX
SDCLKout9
_ ADLY_EN
0
0
DCLKout8
_ DDLY_PD
DCLKout8
_ HSg_PD
DCLKout8
_ ADLYg_PD
DCLKout8
_ADLY _PD
CLKout8_9
_PD
SDCLKout9
_PD
SDCLKout9
_POL
DCLKout8
_POL
CLKout9_FMT
CLKout10
_11 _ODL
CLKout10
_11_IDL
0x128
0x129
0x12B
0
DCLKout10_DIV
DCLKout10_DDLY_CNTH
DCLKout10_ADLY
SDCLKout11
DCLKout10_DDLY_CNTL
DCLKout10
DCLKout10_MUX
_ ADLY_MUX
SDCLKout11_DDLY
SDCLKout11_ADLY
SDCLKout11_DIS_MODE
CLKout10_FMT
DCLKout10
_HS
SDCLKout11
_HS
0x12C
0x12D
0x12E
0x12F
0
0
_MUX
SDCKLout11
_ ADLY_EN
0
0
DCLKout10
_ DDLY_PD
DCLKout10
_ HSg_PD
DLCLKout10
_ ADLYg_PD
DCLKout10
_ ADLY_PD
CLKout10
_11_PD
SDCLKout11
_PD
SDCLKout11
_POL
DCLKout10
_POL
CLKout11_FMT
CLKout12
_13 _ODL
CLKout12
_13_IDL
0x130
0x131
0x133
0
DCLKout12_DIV
DCLKout12_DDLY_CNTH
DCLKout12_ADLY
SDCLKout13
DCLKout12_DDLY_CNTL
DCLKout12_
DCLKout12_MUX
ADLY_MUX
SDCLKout13_DDLY
SDCLKout13_ADLY
SDCLKout13_DIS_MODE
CLKout12_FMT
OSCout_FMT
SYSREF_
DCLKout12
_HS
SDCLKout13
_HS
0x134
0x135
0x136
0x137
0x138
0x139
0
0
_MUX
SDCLKout13
_ ADLY_EN
0
0
DCLKout12
_ DDLY_PD
DCLKout12
_ HSg_PD
DCLKout12
_ ADLYg_PD
DCLKout12
_ ADLY_PD
CLKout12
_13_PD
SDCLKout13
_PD
SDCLKout13
_POL
DCLKout12
_POL
CLKout13_FMT
OSCout
_MUX
0
VCO_MUX
0
0
0
0
0
0
0
0
SYSREF_MUX
CLKin0_MUX
0x13A
0x13B
0x13C
SYSREF_DIV[12:8]
SYSREF_DIV[7:0]
0
0
0
SYSREF_DDLY[12:8]
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Register Maps (continued)
Table 11. LMK0482x Register Map (continued)
ADDRESS
DATA
[11:0]
0x13D
0x13E
7
6
5
4
3
2
1
0
SYSREF_DDLY[7:0]
0
0
0
0
0
0
0
0
0
SYSREF_PULSE_CNT
PLL2_NCLK
_MUX
PLL1_NCLK
_MUX
FB_MUX
_EN
0x13F
0x140
FB_MUX
SYSREF_GBL
_PD
SYSREF
_DDLY_PD
SYSREF
_PLSR_PD
PLL1_PD
VCO_LDO_PD
VCO_PD
OSCin_PD
SYSREF_PD
DDLYd_
SYSREF_EN
DDLYd12
_EN
DDLYd10
_EN
0x141
0x142
0x143
DDLYd7_EN
DDLYd6_EN
DDLYd4_EN
DDLYd2_EN
DDLYd0_EN
0
0
0
DDLYd_STEP_CNT
SYSREF_DDLY SYNC_1SHOT
SYNC_PLL2
_DLD
SYNC_PLL1
_DLD
SYNC_POL
SYNC_EN
SYNC_MODE
_CLR
_EN
SYNC
_DISSYSREF
0x144
SYNC_DIS12
SYNC_DIS10
SYNC_DIS8
SYNC_DIS6
SYNC_DIS4
SYNC_DIS2
SYNC_DIS0
0x145
0x146
0
0
1
1
1
1
1
1
1
0
CLKin2_EN
CLKin1_EN
CLKin0_EN
CLKin2_TYPE
CLKin1_TYPE
CLKin0_TYPE
CLKin_SEL
_POL
0x147
0x148
0x149
0x14A
0x14B
CLKin_SEL_MODE
CLKin1_OUT_MUX
CLKin0_OUT_MUX
0
0
0
0
CLKin_SEL0_MUX
CLKin_SEL1_MUX
RESET_MUX
CLKin_SEL0_TYPE
CLKin_SEL1_TYPE
RESET_TYPE
SDIO_RDBK
_TYPE
0
HOLDOVER
_ FORCE
MAN_DAC
_EN
LOS_TIMEOUT
LOS_EN
TRACK_EN
MAN_DAC[9:8]
0x14C
0x14D
0x14E
0x14F
MAN_DAC[7:0]
0
0
DAC_TRIP_LOW
DAC_TRIP_HIGH
DAC_CLK_MULT
DAC_CLK_CNTR
HOLDOVER
_HITLESS
_SWITCH
CLKin
_OVERRIDE
HOLDOVER
_ PLL1_DET
HOLDOVER
_LOS _DET
HOLDOVER
_VTUNE_DET
HOLDOVER
_EN
0x150
0
0
0
0x151
0x152
0x153
0x154
0x155
0x156
0x157
0x158
0x159
0x15A
0
0
0
0
0
HOLDOVER_DLD_CNT[13:8]
HOLDOVER_DLD_CNT[7:0]
CLKin0_R[13:8]
0
0
0
0
CLKin0_R[7:0]
CLKin1_R[7:0]
CLKin2_R[7:0]
PLL1_N[7:0]
CLKin1_R[13:8]
CLKin2_R[13:8]
PLL1_N[13:8]
PLL1
_CP_TRI
PLL1
_CP_POL
0x15B
PLL1_WND_SIZE
PLL1_CP_GAIN
0x15C
0x15D
0x15E
0x15F
0x160
0x161
0
0
0
0
0
0
PLL1_DLD_CNT[13:8]
PLL1_DLD_CNT[7:0]
PLL1_R_DLY
PLL1_N_DLY
PLL1_LD_MUX
0
PLL1_LD_TYPE
0
PLL2_R[11:8]
PLL2_R[7:0]
OSCin_FREQ
PLL2
_XTAL_EN
PLL2
_REF_2X_EN
0x162
PLL2_P
0
0x163
0x164
0x165
0
0
0
0
0
PLL2_N_CAL[17:16]
PLL2_N_CAL[15:8]
PLL2_N_CAL[7:0]
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Register Maps (continued)
Table 11. LMK0482x Register Map (continued)
ADDRESS
[11:0]
DATA
7
6
5
4
3
2
1
0
1
PLL2_FCAL
_DIS
0x166
0
0
0
0
0
PLL2_N[17:16]
0x167
0x168
PLL2_N[15:8]
PLL2_N[7:0]
PLL2
_CP_POL
PLL
2_CP_TRI
0x169
0x16A
0
0
PLL2_WND_SIZE
PLL2_CP_GAIN
SYSREF_REQ_
EN
PLL2_DLD_CNT[15:8]
0x16B
0x16C
0x16D
0x16E
0x171
0x172
0x173
0x174
0x17C
0x17D
PLL2_DLD_CNT[7:0]
PLL2_LF_R4
0
0
PLL2_LF_R3
PLL2_LF_C4
PLL2_LF_C3
PLL2_LD_MUX
PLL2_LD_TYPE
1
0
0
0
0
1
0
1
0
0
0
1
1
0
0
0
0
0
0
PLL2_PD
0
0
0
0
PLL2_PRE_PD
0
0
VCO1_DIV
OPT_REG_1
OPT_REG_2
RB_PLL1_
LD_LOST
CLR_PLL1_
LD_LOST
0x182
0x183
0
0
0
0
0
0
0
0
0
0
RB_PLL1_LD
RB_PLL2_LD
RB_PLL2_
LD_LOST
CLR_PLL2_
LD_LOST
RB_CLKin2_
SEL
RB_CLKin1_
SEL
RB_CLKin0_
SEL
RB_CLKin1_
LOS
RB_CLKin0_
LOS
0x184
0x185
0x188
RB_DAC_VALUE[9:8]
X
RB_DAC_VALUE[7:0]
RB_
HOLDOVER
0
0
0
X
X
X
X
0x1FFD
0x1FFE
0x1FFF
SPI_LOCK[23:16]
SPI_LOCK[15:8]
SPI_LOCK[7:0]
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9.7 Device Register Descriptions
The following section details the fields of each register, the power-on reset defaults, and specific descriptions of
each bit.
In some cases, similar fields are located in multiple registers. In this case, specific outputs may be designated as
X or Y. In these cases, the X represents even numbers from 0 to 12, and the Y represents odd numbers from 1
to 13. In the case where X and Y are both used in a bit name, then Y = X + 1.
9.7.1 System Functions
9.7.1.1 RESET, SPI_3WIRE_DIS
This register contains the RESET function, and a setting to disable 3-wire SPI mode.
Table 12. Register 0x000
BIT
NAME
POR
DEFAULT
DESCRIPTION
0: Normal operation
1: Reset (automatically cleared)
7
RESET
NA
0
0
6:5
Reserved
Disable 3-wire SPI mode. 4-wire SPI mode is enabled by selecting SPI Read back in one
of the output MUX settings. For example, CLKin0_SEL_MUX.
0: 3-wire mode enabled
4
SPI_3WIRE_DIS
NA
0
1: 3-wire mode disabled
3:0
NA
Reserved
9.7.1.2 POWERDOWN
This register contains the POWERDOWN function.
Table 13. Register 0x002
POR
DEFAULT
BIT
7:1
0
NAME
NA
DESCRIPTION
0
Reserved
0: Normal operation
1: Powerdown
POWERDOWN
0
9.7.1.3 ID_DEVICE_TYPE
This register contains the product device type. This is read only register.
Table 14. Register 0x003
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:0
ID_DEVICE_TYPE
6
PLL product device type
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9.7.1.4 ID_PROD[15:8], ID_PROD
These registers contain the product identifier. This is a read only register.
Table 15. ID_PROD Register Configuration, ID_PROD[15:0]
MSB
LSB
0x004[7:0]
0x005[7:0]
POR
DEFAULT
BIT REGISTERS
FIELD NAME
DESCRIPTION
7:0
7:0
0x004
0x005
ID_PROD[15:8]
ID_PROD
208
91
MSB of the product identifier
LSB of the product identifier
9.7.1.5 ID_MASKREV
This register contains the IC version identifier. This is a read only register.
Table 16. Register 0x006
POR
DEFAULT
BIT
NAME
DESCRIPTION
36
37
32
IC version identifier for LMK04821
IC version identifier for LMK04826
IC version identifier for LMK04828
7:0
ID_MASKREV
9.7.1.6 ID_VNDR[15:8], ID_VNDR
These registers contain the vendor identifier. This is a read only register.
Table 17. ID_VNDR Register Configuration, ID_VNDR[15:0]
MSB
LSB
0x00C[7:0]
0x00D[7:0]
Table 18. Registers 0x00C, 0x00D
BIT REGISTERS
NAME
POR
DEFAULT
DESCRIPTION
7:0
7:0
0x00C
0x00D
ID_VNDR[15:8]
ID_VNDR
81
MSB of the vendor identifier
LSB of the vendor identifier
4
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9.7.2 (0x100 - 0x138) Device Clock and SYSREF Clock Output Controls
9.7.2.1 CLKoutX_Y_ODL, CLKoutX_Y_IDL, DCLKoutX_DIV
These registers control the input and output drive level, as well as the device clock out divider values.
Table 19. Registers 0x100, 0x108, 0x110, 0x118, 0x120, 0x128, and 0x130
POR
DEFAULT
BIT
7
NAME
NA
DESCRIPTION
0
Reserved
Output drive level. Setting this bit increases the current to the CLKoutX_Y output buffers,
which can slightly improve noise floor.
6
CLKoutX_Y_ODL
0
0
Input drive level. Setting this bit increases the current to the clock distribution buffer
sourcing CLKoutX_Y, which can slightly improve noise floor.
5
CLKoutX_Y_IDL
DCLKoutX_DIV
DCLKoutX_DIV sets the divide value for the clock output; the divide may be even or odd.
Both even or odd divides output a 50% duty cycle clock if duty cycle correction (DCC) is
selected.
Divider is unused if DCLKoutX_MUX = 2 (bypass), equivalent divide of 1.
X = 0 → 2
X = 2 → 4
X = 4 → 8
X = 6 → 8
X = 8 → 8
X = 10 → 8
X = 12 → 2
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
...
Divider Value
32
4:0
(1)
1
2
...
30 (0x1E)
31 (0x1F)
30
31
(1) Not valid if DCLKoutX_MUX = 0, divider only. Not valid if DCLKoutX_MUX = 3 (analog delay + divider) and DCLKoutX_ADLY_MUX = 0
(without duty cycle correction/halfstep).
9.7.2.2 DCLKoutX_DDLY_CNTH, DCLKoutX_DDLY_CNTL
This register controls the digital delay high and low count values for the device clock outputs.
Table 20. Registers 0x101, 0x109, 0x111, 0x119, 0x121, 0x129, 0x131
POR
DEFAULT
BIT
NAME
DESCRIPTION
Number of clock cycles the output is high when digital delay is engaged.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
...
Delay Values
16
DCLKoutX
_DDLY_CNTH
7:4
5
Reserved
2
...
15 (0x0F)
15
Number of clock cycles the output is low when dynamic digital delay is engaged.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
...
Delay Values
16
DCLKoutX
_DDLY_CNTL
3:0
5
Reserved
2
...
15 (0x0F)
15
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9.7.2.3 DCLKoutX_ADLY, DCLKoutX_ADLY_MUX, DCLKout_MUX
These registers control the analog delay properties for the device clocks.
Table 21. Registers 0x103, 0x10B, 0x113, 0x11B, 0x123, 0x12B, 0x133
POR
DEFAULT
BIT
NAME
DESCRIPTION
Device clock analog delay value. Delay step size is 25 ps. DCLKoutX_ADLY_PD = 0
(DCLK analog delay powered up) also adds a fixed 500-ps delay. Effective range is 500 ps
to 1075 ps.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
...
Delay Value
0 ps
7:3
DCLKoutX_ALDY
0
25 ps
50 ps
...
23 (0x17)
575 ps
This register selects the input to the analog delay for the device clock. Used when
DCLKoutX_MUX = 3.
0: Divided without duty cycle correction or half step.
DCLKoutX_ADLY
_MUX
2
0
0
(1)
1: Divided with duty cycle correction and half step.
This selects the input to the device clock buffer.
Field Value
Mux Output
(1)
0 (0x0)
Divider only
1:0
DCLKoutX_MUX
Divider with duty cycle Correction
and half step
1 (0x1)
2 (0x2)
3 (0x3)
Bypass
Analog delay + divider
(1) DCLKoutX_DIV = 1 is not valid when DCLKoutX_MUX = 0. DCLKoutX_DIV = 1 is valid for DCLKoutX_MUX = 1, or DCLKoutX_MUX = 3
and DCLKoutX_ADLY_MUX = 1.
9.7.2.4 DCLKoutX_HS, SDCLKoutY_MUX, SDCLKoutY_DDLY, SDCLKoutY_HS
These registers set the half step for the device clock, the SYSREF output MUX, the SYSREF clock digital delay,
and half step.
Table 22. Registers 0x104, 0x10C, 0x114, 0x11C, 0x124, 0x12C, 0x134
BIT
7
NAME
NA
POR
DEFAULT
DESCRIPTION
0
0
Reserved
Sets the device clock half step value. Half step must be zero (0) for a divide of 1.
6
DCLKoutX_HS
0: 0 cycles
1: -0.5 cycles
Sets the input the the SDCLKoutX outputs.
0: Device clock output
1: SYSREF output
5
4:1
0
SDCLKoutY_MUX
SDCLKoutY_DDLY
SDCLKoutY_HS
0
0
0
Sets the number of VCO cycles to delay the SDCLKout by.
Field Value
0 (0x00)
Delay Cycles
Bypass
1 (0x01)
2
2 (0x02)
3
...
...
10 (0x0A)
11
11 to 15 (0x0B to 0x0F)
Reserved
Sets the SYSREF clock half-step value.
0: 0 cycles
1: -0.5 cycles
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9.7.2.5 SDCLKoutY_ADLY_EN, SDCLKoutY_ADLY
These registers set the analog delay parameters for the SYSREF outputs.
Table 23. Registers 0x105, 0x10D, 0x115, 0x11D, 0x125, 0x12D, 0x135
BIT
7:5
4
NAME
POR
DEFAULT
DESCRIPTION
NA
0
Reserved
Enables analog delay for the SYSREF output.
SDCLKoutY
_ADLY_EN
0
0: Disabled
1: Enabled
Sets the analog delay value for the SYSREF output. Step size is 150 ps, except first step
(600 ps). SDCLKoutY_ADLY_EN = 1 (SDCLK analog delay enabled) also adds a fixed
700-ps delay. Effective range is 700 ps to 2950 ps.
Field Value
0 (0x0)
1 (0x1)
2 (0x2)
3 (0x3)
...
Delay Value
0 ps
SDCLKoutY
_ADLY
600 ps
3:0
0
750 ps (+150 ps from 0x1)
900 ps (+150 ps from 0x2)
...
14 (0xE)
15 (0xF)
2100 ps (+150 ps from 0xD)
2250 ps (+150 ps from 0xE)
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9.7.2.6 DCLKoutX_DDLY_PD, DCLKoutX_HSg_PD, DCLKout_ADLYg_PD, DCLKout_ADLY_PD,
DCLKoutX_Y_PD, SDCLKoutY_DIS_MODE, SDCLKoutY_PD
This register controls the power-down functions for the digital delay, glitchless half step, glitchless analog delay,
analog delay, outputs, and SYSREF disable modes.
Table 24. Registers 0x106, 0x10E, 0x116, 0x11E, 0x126, 0x12E, 0x136
BIT
NAME
POR DEFAULT
DESCRIPTION
Powerdown the device clock digital delay circuitry.
0: Enabled
1: Powerdown
DCLKoutX
_DDLY_PD
7
0
Powerdown the device clock glitchless half-step feature.
0: Enabled
1: Powerdown
DCLKoutX
_HSg_PD
6
5
4
1
1
1
Powerdown the device clock glitchless analog delay feature.
0: Enabled, analog delay step size of one code is glitchless between values 1 to 23.
1: Powerdown
DCLKoutX
_ADLYg_PD
Powerdown the device clock analog delay feature.
0: Enabled
1: Powerdown
DCLKoutX
_ADLY_PD
X_Y = 0_1 → 1
X_Y = 2_3 → 1
X_Y = 4_5 → 0
X_Y = 6_7 → 0
X_Y = 8_9 → 0
X_Y = 10_11 → 0
X_Y = 12_13 → 1
Powerdown the clock group defined by X and Y.
0: Enabled
1: Powerdown
3
CLKoutX_Y_PD
Configures the output state of the SYSREF
Field Value
0 (0x00)
Disable Mode
Active in normal operation
1 (0x01)
If SYSREF_GBL_PD = 1, the output is a
logic low, otherwise it is active.
SDCLKoutY
_DIS_MODE
2:1
0
1
2 (0x02)
3 (0x03)
If SYSREF_GBL_PD = 1, the output is a
nominal Vcm voltage(1), otherwise it is
active.
Output is a nominal Vcm voltage(1)
0
SDCLKoutY_PD
Powerdown SDCLKoutY and set to the state defined by SDCLKoutY_DIS_MODE
(1) If LVPECL mode is used with emitter resistors to ground, the output Vcm is ~0 V, and each pin is ~0 V.
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9.7.2.7 SDCLKoutY_POL, SDCLKoutY_FMT, DCLKoutX_POL, DCLKoutX_FMT
These registers configure the output polarity, and format.
Table 25. Registers 0x107, 0x10F, 0x117, 0x11F, 0x127, 0x12F, 0x137
BIT
POR
DEFAULT
NAME
DESCRIPTION
Sets the polarity of clock on SDCLKoutY when device clock output is selected with
SDCLKoutY_MUX.
0: Normal
7
SDCLKoutY_POL
0
1: Inverted
Sets the output format of the SYSREF clocks
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
Output Format
Powerdown
LVDS
HSDS 6 mA
HSDS 8 mA
HSDS 10 mA
LVPECL 1600 mV
LVPECL 2000 mV
LCPECL
6:4
SDCLKoutY_FMT
DCLKoutX_POL
DCLKoutX_FMT
0
Sets the polarity of the device clocks from the DCLKoutX outputs
3
0
0: Normal
1: Inverted
Sets the output format of the device clocks.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
Output Format
LMK04821: 0
LMK04826/
LMK04828:
X = 0 → 0
X = 2 → 0
X = 4 → 1
X = 6 → 1
X = 8 → 1
X = 10 → 1
X = 12 → 0
Powerdown
LVDS
HSDS 6 mA
HSDS 8 mA
HSDS 10 mA
LVPECL 1600 mV
LVPECL 2000 mV
LCPECL
2:0
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9.7.3 SYSREF, SYNC, and Device Config
9.7.3.1 VCO_MUX, OSCout_MUX, OSCout_FMT
This register selects the clock distribution source, and OSCout parameters.
Table 26. Register 0x138
POR
DEFAULT
BIT
NAME
DESCRIPTION
7
NA
0
Reserved
Selects clock distribution path source from VCO0, VCO1, or CLKin (external VCO)
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
VCO Selected
VCO 0
6:5
VCO_MUX
0
0
VCO 1
CLKin1 (external VCO)
Reserved
Select the source for OSCout:
0: Buffered OSCin
4
OSCout_MUX
1: Feedback mux
Selects the output format of OSCout. When powered down, these pins may be used as
CLKin2.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
8 (0x08)
9 (0x09)
10 (0x0A)
11 (0x0B)
12 (0x0C)
13 (0x0D)
14 (0x0E)
OSCout Format
Powerdown (CLKin2)
LVDS
Reserved
Reserved
LVPECL 1600 mVpp(1)
LVPECL 2000 mVpp(1)
LVCMOS (Norm / Inv)
LVCMOS (Inv / Norm)
LVCMOS (Norm / Norm)
LVCMOS (Inv / Inv)
LVCMOS (Off / Norm)
LVCMOS (Off / Inv)
LVCMOS (Norm / Off)
LVCMOS (Inv / Off)
LVCMOS (Off / Off)
3:0
OSCout_FMT
4
(1) When set to an LVPECL drive format, OSCout emitter resistors must be 240 Ω to GND.
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9.7.3.2 SYSREF_CLKin0_MUX, SYSREF_MUX
This register sets the source for the SYSREF outputs. Refer to Figure 13 and SYNC/SYSREF.
Table 27. Register 0x139
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:3
NA
0
Reserved
Selects the SYSREF output from SYSREF_MUX or CLKin0 direct
Field Value
SYSREF Source
SYSREF_
CLKin0_MUX
2
0
0
0
SYSREF Mux
1
Selects the SYSREF source.
Field Value
CLKin0 direct (from CLKin0_OUT_MUX)
SYSREF Source
Normal SYNC
0 (0x00)
1:0
SYSREF_MUX
1 (0x01)
Re-clocked
2 (0x02)
SYSREF pulser
SYSREF continuous
3 (0x03)
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9.7.3.3 SYSREF_DIV[12:8], SYSREF_DIV[7:0]
These registers set the value of the SYSREF output divider.
Table 28. Registers 0x13A, 0x13B
MSB
LSB
0x13A[4:0]
0x13B[7:0]
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7:5
0x13A
NA
0
Reserved
Divide value for the SYSREF outputs.
Field Value
0x00 to 0x07
8 (0x08)
Divide Value
4:0
0x13A
SYSREF_DIV[12:8]
SYSREF_DIV[7:0]
12
Reserved
8
9
9 (0x09)
...
...
7:0
0x13B
0
8190 (0x1FFE)
8191 (0X1FFF)
8190
8191
9.7.3.4 SYSREF_DDLY[12:8], SYSREF_DDLY[7:0]
These registers set the delay of the SYSREF digital delay value.
Table 29. SYSREF Digital Delay Register Configuration, SYSREF_DDLY[12:0]
MSB
LSB
0x13C[4:0]
0x13D[7:0]
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7:5
0x13C
NA
0
Reserved
Sets the value of the SYSREF digital delay.
Field Value
0x00 to 0x07
8 (0x08)
Delay Value
4:0
0x13C
SYSREF_DDLY[12:8]
SYSREF_DDLY[7:0]
0
Reserved
8
9
9 (0x09)
...
...
7:0
0x13D
8
8190 (0x1FFE)
8191 (0X1FFF)
8190
8191
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9.7.3.5 SYSREF_PULSE_CNT
This register sets the number of SYSREF pulses if SYSREF is not in continuous mode. See
SYSREF_CLKin0_MUX, SYSREF_MUX for further description of SYSREF's outputs.
Programming the register causes the specified number of pulses to be output if "SYSREF Pulses" is selected by
SYSREF_MUX and SYSREF functionality is powered up.
Table 30. Register 0x13E
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:2
NA
0
Reserved
Sets the number of SYSREF pulses generated when not in continuous mode.
See SYSREF_CLKin0_MUX, SYSREF_MUX for more information on SYSREF modes.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
Number of Pulses
1 pulse
1:0
SYSREF_PULSE_CNT
3
2 pulses
4 pulses
8 pulses
9.7.3.6 PLL2_NCLK_MUX, PLL1_NCLK_MUX, FB_MUX, FB_MUX_EN
This register controls the feedback feature.
Table 31. Register 0x13F
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:5
NA
0
Reserved
Selects the input to the PLL2 N divider
0: PLL prescaler
1: Feedback mux
4
3
PLL2_NCLK_MUX
PLL1_NCLK_MUX
0
0
Selects the input to the PLL1 N delay
0: OSCin
1: Feedback mux
When in zero-delay mode, the feedback mux selects the clock output to be fed back into
the PLL1 N divider.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
Source
DCLKout6
2:1
FB_MUX
0
0
DCLKout8
SYSREF Divider
External
When using zero-delay, FB_MUX_EN must be set to 1 to power up the feedback mux.
0: Feedback mux powered down
0
FB_MUX_EN
1: Feedback mux enabled
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9.7.3.7 PLL1_PD, VCO_LDO_PD, VCO_PD, OSCin_PD, SYSREF_GBL_PD, SYSREF_PD,
SYSREF_DDLY_PD, SYSREF_PLSR_PD
This register contains powerdown controls for OSCin and SYSREF functions.
Table 32. Register 0x140
POR
DEFAULT
BIT
NAME
DESCRIPTION
Powerdown PLL1
0: Normal operation
1: Powerdown
7
PLL1_PD
0
Powerdown VCO_LDO
0: Normal operation
1: Powerdown
6
5
4
VCO_LDO_PD
VCO_PD
0
0
0
Powerdown VCO
0: Normal operation
1: Powerdown
Powerdown the OSCin port.
0: Normal operation
1: Powerdown
OSCin_PD
Powerdown individual SYSREF outputs depending on the setting of
SDCLKoutY_DIS_MODE for each SYSREF output. SYSREF_GBL_PD allows many
SYSREF outputs to be controlled through a single bit.
0: Normal operation
3
2
SYSREF_GBL_PD
SYSREF_PD
0
1
1: Activate powerdown mode
Powerdown the SYSREF circuitry and divider. If powered down, SYSREF output mode
cannot be used. SYNC cannot be provided either.
0: SYSREF can be used as programmed by individual SYSREF output registers.
1: Powerdown
Powerdown the SYSREF digital delay circuitry.
0: Normal operation, SYSREF digital delay may be used. Must be powered up during
SYNC for deterministic phase relationship with other clocks.
1: Powerdown
1
0
SYSREF_DDLY_PD
SYSREF_PLSR_PD
1
1
Powerdown the SYSREF pulse generator.
0: Normal operation
1: Powerdown
9.7.3.8 DDLYdSYSREF_EN, DDLYdX_EN
This register enables dynamic digital delay for enabled device clocks and SYSREF when DDLYd_STEP_CNT is
programmed.
Table 33. Register 0x141
BIT
7
NAME
DDLYd _SYSREF_EN
DDLYd12_EN
DDLYd10_EN
DDLYd8_EN
POR DEFAULT
DESCRIPTION
Enables dynamic digital delay on SYSREF outputs
Enables dynamic digital delay on DCLKout12
Enables dynamic digital delay on DCLKout10
Enables dynamic digital delay on DCLKout8
Enables dynamic digital delay on DCLKout6
Enables dynamic digital delay on DCLKout4
Enables dynamic digital delay on DCLKout2
Enables dynamic digital delay on DCLKout0
0
0
0
0
0
0
0
0
6
5
4
0: Disabled
1: Enabled
3
DDLYd6_EN
2
DDLYd4_EN
1
DDLYd2_EN
0
DDLYd0_EN
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9.7.3.9 DDLYd_STEP_CNT
This register sets the number of dynamic digital delay adjustments occur. Upon programming, the dynamic digital
delay adjustment begins for each clock output with dynamic digital delay enabled. Dynamic digital delay can only
be started by SPI.
Other registers must be set: SYNC_MODE = 3
Table 34. Register 0x142
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:4
NA
0
Reserved
Sets the number of dynamic digital delay adjustments that occur.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
...
SYNC Generation
No adjust
1 step
3:0
DDLYd_STEP_CNT
0
2 steps
3 steps
...
14 (0x0E)
15 (0x0F)
14 steps
15 steps
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9.7.3.10 SYSREF_CLR, SYNC_1SHOT_EN, SYNC_POL, SYNC_EN, SYNC_PLL2_DLD, SYNC_PLL1_DLD,
SYNC_MODE
This register sets general SYNC parameters such as polarization, and mode. Refer to Figure 13 for block
diagram. Refer to Table 1 for using SYNC_MODE for specific SYNC use cases.
Table 35. Register 0x143
POR
DEFAULT
BIT
NAME
DESCRIPTION
Resets and arms the SDCLKoutY_DDLY path, allowing local digital delays to take effect
after a SYNC event. Except during the SYSREF setup procedure (see SYNC/SYSREF), this
bit should always be programmed to 0. While this bit is set, extra current is used. Refer to
Table 87.
7
SYSREF_CLR
1
SYNC one shot enables edge-sensitive SYNC.
0: SYNC is level sensitive and outputs are held in SYNC while SYNC is asserted.
1: SYNC is edge sensitive, outputs are SYNCed on rising edge of SYNC. This results in the
clock being held in SYNC for a minimum amount of time.
6
SYNC_1SHOT_EN
0
Sets the polarity of the SYNC pin.
0: Normal
1: Inverted
5
4
SYNC_POL
SYNC_EN
0
1
Enables the SYNC functionality.
0: Disabled
1: Enabled
0: Off
3
2
SYNC_PLL2_DLD
SYNC_PLL1_DLD
0
0
1: Assert SYNC until PLL2 DLD = 1
0: Off
1: Assert SYNC until PLL1 DLD = 1
Sets the method of generating a SYNC event.
Field Value
SYNC Generation
Prevents SYNC pin, SYNC_PLL1_DLD flag, or
SYNC_PLL2_DLD flag from generating a SYNC event.
0 (0x00)
SYNC event generated from SYNC pin or, if enabled, the
SYNC_PLL1_DLD flag or SYNC_PLL2_DLD flag.
1 (0x01)
2 (0x02)
1:0
SYNC_MODE
1
For use with pulser – SYNC/SYSREF pulses are generated by
pulser block through the SYNC pin or, if enabled, the
SYNC_PLL1_DLD flag or SYNC_PLL2_DLD flag.
For use with pulser – SYNC/SYSREF pulses are generated by
pulser block when programming register 0x13E
3 (0x03)
(SYSREF_PULSE_CNT) is written to (see SYSREF Pulser).
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9.7.3.11 SYNC_DISSYSREF, SYNC_DISX
SYNC_DISX prevents a clock output from being synchronized or interrupted by a SYNC event, or when
outputting SYSREF.
Table 36. Register 0x144
POR
DEFAULT
BIT
NAME
DESCRIPTION
Prevents the SYSREF clocks from becoming synchronized during a SYNC event. If
SYNC_DISSYSREF is enabled, it continues to operate normally during a SYNC event.
7
SYNC_DISSYSREF
0
6
5
4
3
2
1
0
SYNC_DIS12
SYNC_DIS10
SYNC_DIS8
SYNC_DIS6
SYNC_DIS4
SYNC_DIS2
SYNC_DIS0
0
0
0
0
0
0
0
Prevents the device clock output from becoming synchronized during a SYNC event or
SYSREF clock. If SYNC_DIS bit for a particular output is enabled, then it continues to
operate normally during a SYNC event or SYSREF clock.
9.7.3.12 Fixed Registers (0x145, 0x171 - 0x172)
Always program this register to value 127.
Table 37. Register 0x145
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:0
Fixed Register
0
Always program to 127
Always program this register to value 170.
Table 38. Register 0x171
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:0
Fixed Register
10 (0x0A)
Always program to 170 (0xAA)
Always program this register to value 2.
Table 39. Register 0x172
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:0
Fixed Register
0
Always program to 2 (0x02)
9.7.4 (0x146 - 0x149) CLKin Control
9.7.4.1 CLKin2_EN, CLKin1_EN, CLKin0_EN, CLKin2_TYPE, CLKin1_TYPE, CLKin0_TYPE
This register has CLKin enable and type controls.
Table 40. Register 0x146
BIT
7:6
5
POR
DEFAULT
NAME
DESCRIPTION
NA
0
Reserved
Enable CLKin2 to be used during auto-switching of CLKin_SEL_MODE.
0: Not enabled for auto mode
CLKin2_EN
CLKin1_EN
0
1: Enabled for auto mode
Enable CLKin1 to be used during auto-switching of CLKin_SEL_MODE.
0: Not enabled for auto mode
4
1
1: Enabled for auto mode
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Table 40. Register 0x146 (continued)
BIT
POR
DEFAULT
NAME
DESCRIPTION
Enable CLKin0 to be used during auto-switching of CLKin_SEL_MODE.
0: Not enabled for auto mode
3
CLKin0_EN
1
1: Enabled for auto mode
2
1
CLKin2_TYPE
CLKin1_TYPE
0
0
There are two buffer types for CLKin0, 1, and 2: bipolar and CMOS.
Bipolar is recommended for differential inputs such as LVDS or
LVPECL. CMOS is recommended for DC-coupled single-ended
inputs.
0: Bipolar
1: MOS
When using bipolar, CLKinX and CLKinX* must be AC coupled.
When using CMOS, CLKinX and CLKinX* may be AC or DC coupled
if the input signal is differential. If the input signal is single-ended, the
used input may be either AC or DC coupled, and the unused input
must AC grounded (see Driving CLKin and OSCin Pins With a Single-
Ended Source).
0
CLKin0_TYPE
0
9.7.4.2 CLKin_SEL_POL, CLKin_SEL_MODE, CLKin1_OUT_MUX, CLKin0_OUT_MUX
Table 41. Register 0x147
POR
DEFAULT
BIT
NAME
DESCRIPTION
Inverts the CLKin polarity for use in pin select mode.
7
CLKin_SEL_POL
0
0: Active high
1: Active low
Sets the mode used in determining the reference for PLL1.
Field Value
CLKin Mode
CLKin0 manual
CLKin1 manual
CLKin2 manual
Pin select mode
Auto mode
0 (0x00)
1 (0x01)
2 (0x02)
6:4
CLKin_SEL_MODE
3
3 (0x03)
4 (0x04)
5 (0x05)
Reserved
6 (0x06)
Reserved
7 (0x07)
Reserved
Selects where the output of the CLKin1 buffer is directed.
Field Value
CLKin1 Destination
0 (0x00)
Fin
3:2
1:0
CLKin1_OUT_MUX
CLKin0_OUT_MUX
2
2
1 (0x01)
2 (0x02)
3 (0x03)
Feedback mux (zero-delay mode)
PLL1
Off
Selects where the output of the CLKin0 buffer is directed.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
CLKin0 Destination
SYSREF mux
Reserved
PLL1
Off
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9.7.4.3 CLKin_SEL0_MUX, CLKin_SEL0_TYPE
This register has CLKin_SEL0 controls.
Table 42. Register 0x148
BIT
NAME
POR
DEFAULT
DESCRIPTION
7:6
NA
0
Reserved
This set the output value of the CLKin_SEL0 pin. This register only applies if
CLKin_SEL0_TYPE is set to an output mode
Field Value
Output Format
Logic low
0 (0x00)
1 (0x01)
CLKin0 LOS
CLKin0 selected
DAC locked
DAC low
2 (0x02)
5:3
CLKin_SEL0_MUX
0
3 (0x03)
4 (0x04)
5 (0x05)
DAC high
6 (0x06)
SPI readback
Reserved
7 (0x07)
This sets the I/O type of the CLKin_SEL0 pin.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
Configuration
Input
Function
Input mode, see Input
Clock Switching - Pin
Select Mode for
Input with pull-up resistor
Input with pull-down resistor
Output (push-pull)
2:0
CLKin_SEL0_TYPE
2
description of input mode.
Output modes; the
CLKin_SEL0_MUX
register for description of
outputs.
Output inverted (push-pull)
Reserved
Output (open drain)
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9.7.4.4 SDIO_RDBK_TYPE, CLKin_SEL1_MUX, CLKin_SEL1_TYPE
This register has CLKin_SEL1 controls and register readback SDIO pin type.
Table 43. Register 0x149
POR
DEFAULT
BIT
NAME
DESCRIPTION
7
NA
0
Reserved
Sets the SDIO pin to open drain when during SPI readback in 3-wire mode.
6
SDIO_RDBK_TYPE
1
0: Output, push-pull
1: Output, open drain.
This set the output value of the CLKin_SEL1 pin. This register only applies if
CLKin_SEL1_TYPE is set to an output mode.
Field Value
Output Format
Logic low
0 (0x00)
1 (0x01)
CLKin1 LOS
CLKin1 selected
DAC locked
DAC low
2 (0x02)
5:3
CLKin_SEL1_MUX
0
3 (0x03)
4 (0x04)
5 (0x05)
DAC high
6 (0x06)
SPI readback
Reserved
7 (0x07)
This sets the I/O type of the CLKin_SEL1 pin.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
Configuration
Input
Function
Input mode, see Input Clock
Switching - Pin Select Mode for
description of input mode.
Input with pull-up resistor
Input with pull-down resistor
Output (push-pull)
Output inverted (push-pull)
Reserved
2:0
CLKin_SEL1_TYPE
2
Output modes; see the
CLKin_SEL1_MUX register for
description of outputs.
Output (open drain)
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9.7.5 RESET_MUX, RESET_TYPE
This register contains control of the RESET pin.
Table 44. Register 0x14A
POR
DEFAUL
T
BIT
NAME
DESCRIPTION
7:6
NA
0
Reserved
This sets the output value of the RESET pin. This register only applies if RESET_TYPE is set to an
output mode.
Field Value
Output Format
Logic low
0 (0x00)
1 (0x01)
Reserved
5:3
RESET_MUX
0
2 (0x02)
CLKin2 selected
DAC locked
DAC low
3 (0x03)
4 (0x04)
5 (0x05)
DAC high
6 (0x06)
This sets the I/O type of the RESET pin.
Field Value
SPI readback
Configuration
Function
0 (0x00)
Input
Reset mode
Reset pin high = reset
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
Input with pull-up resistor
Input with pull-down resistor
Output (push-pull)
2:0 RESET_TYPE
2
Output modes; see the
RESET_MUX register for
description of outputs.
Output inverted (push-pull)
Reserved
Output (open drain)
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9.7.6 (0x14B - 0x152) Holdover
9.7.6.1 LOS_TIMEOUT, LOS_EN, TRACK_EN, HOLDOVER_FORCE, MAN_DAC_EN, MAN_DAC[9:8]
This register contains the holdover functions.
Table 45. Register 0x14B
POR
DEFAULT
BIT
NAME
DESCRIPTION
This controls the amount of time in which no activity on a CLKin forces a clock switch
event.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
Timeout
370 kHz (2.7 µs)
2.1 MHz (480 ns)
8.8 MHz (115 ns)
22 MHz (45 ns)
7:6
LOS_TIMEOUT
0
Enables the LOS (loss-of-signal) timeout control. Valid only for MOS clock inputs. To
ensure LOS is valid for AC-coupled inputs, no termination is allowed between CLKinX and
CLKinX* pins unless DC-blocked. For example, 100-Ω termination across CLKin0 and
CLKin0* pins on the IC side of AC coupling capacitors would invalidate the LOS detector. If
termination is required, it should be placed on the other side of the AC coupling capacitors,
away from the IC pins.
5
LOS_EN
0
0: Disabled
1: Enabled
Enable the DAC to track the PLL1 tuning voltage, optionally for use in holdover mode. After
device reset, tracking starts at DAC code = 512 (midrange).
Tracking can be used to monitor PLL1 voltage in any mode.
0: Disabled
4
3
TRACK_EN
1
0
1: Enabled, only tracks when PLL1 is locked.
This bit forces holdover mode. When holdover mode is forced, if MAN_DAC_EN = 1, then
the DAC sets the programmed MAN_DAC value. Otherwise the tracked DAC value sets the
DAC voltage.
0: Disabled
1: Enabled
HOLDOVER
_FORCE
This bit enables the manual DAC mode.
2
MAN_DAC_EN
MAN_DAC[9:8]
1
2
0: Automatic
1: Manual
1:0
See MAN_DAC[9:8], MAN_DAC[7:0] for more information on the MAN_DAC settings.
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9.7.6.2 MAN_DAC[9:8], MAN_DAC[7:0]
These registers set the value of the DAC in holdover mode when used manually.
Table 46. MAN_DAC[9:0]
MSB
LSB
0x14B[1:0]
0x14C[7:0]
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
See LOS_TIMEOUT, LOS_EN, TRACK_EN, HOLDOVER_FORCE,
MAN_DAC_EN, MAN_DAC[9:8] for information on these bits.
7:2
0x14B
Sets the value of the manual DAC when in manual DAC mode.
Field Value
0 (0x00)
DAC Value
1:0
0x14B
MAN_DAC[9:8]
MAN_DAC[7:0]
2
0
0
1
1 (0x01)
2 (0x02)
2
...
...
7:0
0x14C
1022 (0x3FE)
1023 (0x3FF)
1022
1023
9.7.6.3 DAC_TRIP_LOW
This register contains the high value at which holdover mode is entered.
Table 47. Register 0x14D
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:6
NA
0
Reserved
Voltage from GND at which holdover is entered if HOLDOVER_VTUNE_DET is enabled.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
...
DAC Trip Value
1 x Vcc / 64
2 x Vcc / 64
3 x Vcc / 64
4 x Vcc / 64
...
5:0
DAC_TRIP_LOW
0
61 (0x17)
62 (0x18)
63 (0x19)
62 x Vcc / 64
63 x Vcc / 64
64 x Vcc / 64
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9.7.6.4 DAC_CLK_MULT, DAC_TRIP_HIGH
This register contains the multiplier for the DAC clock counter, and the low value at which holdover mode is
entered.
Table 48. Register 0x14E
POR
DEFAULT
BIT
NAME
DESCRIPTION
This is the multiplier for the DAC_CLK_CNTR which sets the rate at which the DAC value is
tracked.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
DAC Multiplier Value
4
7:6
DAC_CLK_MULT
0
64
1024
16384
Voltage from Vcc at which holdover is entered if HOLDOVER_VTUNE_DET is enabled.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
...
DAC Trip Value
1 x Vcc / 64
2 x Vcc / 64
3 x Vcc / 64
4 x Vcc / 64
...
5:0
DAC_TRIP_HIGH
0
61 (0x17)
62 (0x18)
63 (0x19)
62 x Vcc / 64
63 x Vcc / 64
64 x Vcc / 64
9.7.6.5 DAC_CLK_CNTR
This register contains the value of the DAC when in tracked mode.
Table 49. Register 0x14F
POR
DEFAULT
BIT
NAME
DESCRIPTION
This with DAC_CLK_MULT set the rate at which the DAC is updated. The update rate (in
seconds) is = DAC_CLK_MULT * DAC_CLK_CNTR / PLL1 PDF (Hz)
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
...
DAC Value
0
1
2
7:0
DAC_CLK_CNTR
127
3
...
253 (0xFD)
254 (0xFE)
255 (0xFF)
253
254
255
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9.7.6.6 CLKin_OVERRIDE, HOLDOVER_PLL1_DET, HOLDOVER_LOS_DET, HOLDOVER_VTUNE_DET,
HOLDOVER_HITLESS_SWITCH, HOLDOVER_EN
This register has controls for enabling clock in switch events.
Table 50. Register 0x150
POR
DEFAULT
BIT
NAME
DESCRIPTION
7
NA
0
Reserved
When CLKin_SEL_MODE = 0/1/2 to select a manual clock input, CLKin_OVERRIDE = 1
forces that clock input. Used with clock distribution mode for best performance.
0: Normal, no override.
CLKin
_OVERRIDE
6
0
1: Force select of only CLKin0/1/2, as specified by CLKin_SEL_MODE in manual mode.
5
4
NA
0
0
Reserved
This enables the HOLDOVER when PLL1 lock detect signal transitions from high to low.
0: PLL1 DLD does not cause a clock switch event
1: PLL1 DLD causes a clock switch event
HOLDOVER
_PLL1_DET
This enables HOLDOVER when PLL1 LOS signal is detected.
0: Disabled
1: Enabled
HOLDOVER
_LOS_DET
3
2
0
0
Enables the DAC Vtune rail detections. When the DAC achieves a specified Vtune, if this
bit is enabled, the current clock input is considered invalid and an input clock switch event
is generated.
0: Disabled
1: Enabled
HOLDOVER
_VTUNE_DET
HOLDOVER
_HITLESS
_SWITCH
Determines whether a clock switch event will enter holdover use hitless switching.
0: Hard Switch
1: Hitless switching (has an undefined switch time)
1
0
1
1
Sets whether holdover mode can be entered when holdover conditions are met.
0: Disabled
1: Enabled
HOLDOVER_EN
9.7.6.7 HOLDOVER_DLD_CNT[13:8], HOLDOVER_DLD_CNT[7:0]
Table 51. HOLDOVER_DLD_CNT[13:0]
MSB
LSB
0x151[5:0]
0x152[7:0]
This register has the number of valid clocks of PLL1 PDF before holdover is exited.
Table 52. Registers 0x151 and 0x152
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7:6
0x151
NA
0
Reserved
The number of valid clocks of PLL1 PDF before holdover mode is exited.
Field Value
0 (0x00)
Count Value
HOLDOVER
_DLD_CNT[13:8]
5:0
0x151
2
0
0
1
1 (0x01)
2 (0x02)
2
...
...
HOLDOVER
_DLD_CNT[7:0]
7:0
0x152
16382 (0x3FFE)
16383 (0x3FFF)
16382
16383
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9.7.7 (0x153 - 0x15F) PLL1 Configuration
9.7.7.1 CLKin0_R[13:8], CLKin0_R[7:0]
Table 53. CLKin0_R[13:0]
MSB
LSB
0x153[5:0]
0x154[7:0]
These registers contain the value of the CLKin0 divider.
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7:6
0x153
NA
0
Reserved
The value of PLL1 R divider when CLKin0 is selected.
Field Value
0 (0x00)
Divide Value
5:0
0x153
CLKin0_R[13:8]
CLKin0_R[7:0]
0
Reserved
1 (0x01)
1
2
2 (0x02)
...
...
7:0
0x154
120
16382 (0x3FFE)
16383 (0x3FFF)
16382
16383
9.7.7.2 CLKin1_R[13:8], CLKin1_R[7:0]
Table 54. CLKin1_R[13:0]
MSB
LSB
0x155[5:0]
0x156[7:0]
These registers contain the value of the CLKin1 R divider.
Table 55. Registers 0x155 and 0x156
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7:6
5:0
0x155
0x155
NA
0
0
Reserved
The value of PLL1 R divider when CLKin1 is selected.
Field Value
0 (0x00)
Divide Value
CLKin1_R[13:8]
CLKin1_R[7:0]
Reserved
1 (0x01)
1
2
2 (0x02)
...
...
7:0
0x156
150
16382 (0x3FFE)
16383 (0x3FFF)
16382
16383
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9.7.7.3 CLKin2_R[13:8], CLKin2_R[7:0]
MSB
LSB
0x157[5:0]
0x158[7:0]
These registers contain the value of the CLKin2 R divider.
Table 56. Registers 0x157 and 0x158
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7:6
0x157
NA
0
0
Reserved
The value of PLL1 R divider when CLKin2 is selected.
Field Value
0 (0x00)
Divide Value
5:0
0x157
CLKin2_R[13:8]
CLKin2_R[7:0]
Reserved
1 (0x01)
1
2
2 (0x02)
...
...
7:0
0x158
150
16382 (0x3FFE)
16383 (0x3FFF)
16382
16383
9.7.7.4 PLL1_N
Table 57. PLL1_N[13:8], PLL1_N[7:0]
PLL1_N[13:0]
MSB
LSB
0x159[5:0]
0x15A[7:0]
These registers contain the N divider value for PLL1.
Table 58. Registers 0x159 and 0x15A
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7:6
5:0
0x159
0x159
NA
0
0
Reserved
The value of PLL1 N divider.
Field Value
0 (0x00)
Divide Value
PLL1_N[13:8]
PLL1_N[7:0]
Not valid
1 (0x01)
1
2
2 (0x02)
7:0
0x15A
120
...
...
16,383 (0x3FFF)
16,383
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9.7.7.5 PLL1_WND_SIZE, PLL1_CP_TRI, PLL1_CP_POL, PLL1_CP_GAIN
This register controls the PLL1 phase detector.
Table 59. Register 0x15B
POR
DEFAULT
BIT
NAME
DESCRIPTION
PLL1_WND_SIZE sets the window size used for digital lock detect for PLL1. If the phase
error between the reference and feedback of PLL1 is less than specified time, the PLL1
lock counter increments.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
Definition
4 ns
7:6
PLL1_WND_SIZE
3
9 ns
19 ns
43 ns
This bit allows for the PLL1 charge pump output pin, CPout1, to be placed into TRI-STATE.
0: PLL1 CPout1 is active
1: PLL1 CPout1 is at TRI-STATE
5
4
PLL1_CP_TRI
PLL1_CP_POL
0
1
PLL1_CP_POL sets the charge pump polarity for PLL1. Many VCXOs use positive slope.
A positive-slope VCXO increases output frequency with increasing voltage. A negative-
slope VCXO decreases output frequency with increasing voltage.
0: Negative-slope VCO/VCXO
1: Positive-slope VCO/VCXO
This bit programs the PLL1 charge pump output current level.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
...
Gain
50 µA
150 µA
250 µA
350 µA
450 µA
...
3:0
PLL1_CP_GAIN
4
14 (0x0E)
15 (0x0F)
1450 µA
1550 µA
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9.7.7.6 PLL1_DLD_CNT[13:8], PLL1_DLD_CNT[7:0]
Table 60. PLL1_DLD_CNT[13:0]
MSB
LSB
0x15C[5:0]
0x15D[7:0]
This register contains the value of the PLL1 DLD counter.
Table 61. Registers 0x15C and 0x15D
BIT REGISTERS
NAME
POR DEFAULT
DESCRIPTION
7:6
0x15C
NA
0
Reserved
The reference and feedback of PLL1 must be within the window of phase
error, as specified by PLL1_WND_SIZE for this many phase detector
cycles, before PLL1 digital lock detect is asserted.
PLL1_DLD
_CNT[13:8]
5:0
0x15C
32
Field Value
0 (0x00)
Delay Value
Reserved
1 (0x01)
1
2 (0x02)
2
3
3 (0x03)
PLL1_DLD
_CNT[7:0]
7:0
0x15D
0
...
...
16,382 (0x3FFE)
16,383 (0x3FFF)
16,382
16,383
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9.7.7.7 PLL1_R_DLY, PLL1_N_DLY
This register contains the delay value for PLL1 N and R delays.
Table 62. Register 0x15E
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:6
NA
0
Reserved
Increasing delay of PLL1_R_DLY causes the outputs to lag from CLKinX. For use in zero-
delay mode.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
Gain
0 ps
205 ps
410 ps
615 ps
820 ps
1025 ps
1230 ps
1435 ps
5:3
PLL1_R_DLY
0
Increasing delay of PLL1_N_DLY causes the outputs to lead from CLKinX. For use in zero-
delay mode.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
Gain
0 ps
205 ps
410 ps
615 ps
820 ps
1025 ps
1230 ps
1435 ps
2:0
PLL1_N_DLY
0
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9.7.7.8 PLL1_LD_MUX, PLL1_LD_TYPE
This register configures the PLL1 LD pin.
Table 63. Register 0x15F
POR
DEFAULT
BIT
NAME
DESCRIPTION
This sets the output value of the Status_LD1 pin.
Field Value
0 (0x00)
MUX Value
Logic low
1 (0x01)
PLL1 DLD
PLL2 DLD
PLL1 and PLL2 DLD
Holdover status
DAC locked
Reserved
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
SPI readback
DAC rail
7:3
PLL1_LD_MUX
1
8 (0x08)
9 (0x09)
DAC low
10 (0x0A)
11 (0x0B)
12 (0x0C)
13 (0x0D)
14 (0x0E)
15 (0x0F)
DAC high
PLL1_N
PLL1_N/2
PLL2_N
PLL2_N/2
PLL1_R
16 (0x10)
PLL1_R/2
17 (0x11)
PLL2_R(1)
PLL2_R/2(1)
18 (0x12)
Sets the I/O type of the Status_LD1 pin.
Field Value
0 (0x00)
TYPE
Reserved
1 (0x01)
Reserved
2:0
PLL1_LD_TYPE
6
2 (0x02)
Reserved
3 (0x03)
Output (push-pull)
Output inverted (push-pull)
Reserved
4 (0x04)
5 (0x05)
6 (0x06)
Output (open drain)
(1) Only valid when PLL2_LD_MUX is not set to 2 (PLL2_DLD) or 3 (PLL1 and PLL2 DLD).
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9.7.8 (0x160 - 0x16E) PLL2 Configuration
9.7.8.1 PLL2_R[11:8], PLL2_R[7:0]
Table 64. PLL2_R[11:0]
MSB
LSB
0x160[3:0]
0x161[7:0]
This register contains the value of the PLL2 R divider.
Table 65. Registers 0x160 and 0x161
BIT REGISTERS
NAME
POR DEFAULT
DESCRIPTION
7:4
0x160
NA
0
Reserved
Valid values for the PLL2 R divider.
Field Value
0 (0x00)
Divide Value
3:0
0x160
PLL2_R[11:8]
PLL2_R[7:0]
0
2
Not valid
1 (0x01)
1
2
2 (0x02)
3 (0x03)
3
7:0
0x161
...
...
4,094 (0xFFE)
4,095 (0xFFF)
4,094
4,095
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9.7.8.2 PLL2_P, OSCin_FREQ, PLL2_XTAL_EN, PLL2_REF_2X_EN
This register sets other PLL2 functions.
Table 66. Register 0x162
POR
DEFAULT
BIT
NAME
DESCRIPTION
The PLL2 N prescaler divides the output of the VCO as selected by Mode_MUX1 and is
connected to the PLL2 N divider.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
Value
8
2
2
3
4
5
6
7
7:5
PLL2_P
2
The frequency of the PLL2 reference input to the PLL2 phase detector (OSCin/OSCin* port)
must be programmed to support proper operation of the frequency calibration routine,
which locks the internal VCO to the target frequency.
Field Value
0 (0x00)
OSCin Frequency
0 to 63 MHz
4:2
OSCin_FREQ
7
1 (0x01)
>63 MHz to 127 MHz
>127 MHz to 255 MHz
Reserved
2 (0x02)
3 (0x03)
4 (0x04)
>255 MHz to 500 MHz
Reserved
5 (0x05) to 7(0x07)
If an external crystal is being used to implement a discrete VCXO, the internal feedback
amplifier must be enabled with this bit to complete the oscillator circuit.
0: Oscillator amplifier disabled
1
0
PLL2_XTAL_EN
0
1
1: Oscillator amplifier enabled
Enabling the PLL2 reference frequency doubler allows for higher phase-detector
frequencies on PLL2 than would normally be allowed with the given VCXO or crystal
frequency.
PLL2_REF_2X_EN
Higher phase-detector frequencies reduce the PLL N values, which makes the design of
wider-loop bandwidth filters possible.
0: Doubler disabled
1: Doubler enabled
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9.7.8.3 PLL2_N_CAL
PLL2_N_CAL[17:0]
PLL2 never uses zero-delay during frequency calibration. These registers contain the value of the PLL2 N divider
used with the PLL2 prescaler during calibration for cascaded zero-delay mode. When calibration is complete,
PLL2 uses the PLL2_N value. Cascaded zero-delay mode occurs when PLL2_NCLK_MUX = 1.
Table 67. Register 0x162
MSB
—
LSB
0x163[1:0]
0x164[7:0]
0x165[7:0]
Table 68. Registers 0x163, 0x164, and 0x165
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7:2
1:0
0x163
0x163
NA
0
Reserved
Field Value
0 (0x00)
Divide Value
PLL2_N
_CAL[17:16]
0
0
Not valid
1 (0x01)
1
7:0
7:0
0x164
0x165
PLL2_N_CAL[15:8]
2 (0x02)
2
...
...
PLL2_N_CAL[7:0]
12
262,143 (0x3FFFF)
262,143
9.7.8.4 PLL2_FCAL_DIS, PLL2_N
This register disables frequency calibration and sets the PLL2 N divider value. Programming register 0x168
starts a VCO calibration routine if PLL2_FCAL_DIS = 0.
Table 69. PLL2_N[17:0]
MSB
—
LSB
0x166[1:0]
0x167[7:0]
0x168[7:0]
Table 70. Registers 0x166, 0x167, and 0x168
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7:3
2
0x166
0x166
NA
0
Reserved
This disables the PLL2 frequency calibration on programming register 0x168.
0: Frequency calibration enabled
PLL2_FCAL_DIS
0
1: Frequency calibration disabled
Field Value
0 (0x00)
Divide Value
1:0
7:0
7:0
0x166
0x167
0x168
PLL2_N[17:16]
PLL2_N[15:8]
PLL2_N[7:0]
0
0
Not valid
1 (0x01)
1
2 (0x02)
2
...
...
12
262,143 (0x3FFFF)
262,143
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9.7.8.5 PLL2_WND_SIZE, PLL2_CP_GAIN, PLL2_CP_POL, PLL2_CP_TRI
This register controls the PLL2 phase detector.
Table 71. Register 0x169
POR
DEFAULT
BIT
NAME
DESCRIPTION
7
NA
0
Reserved
PLL2_WND_SIZE sets the window size used for digital lock detect for PLL2. If the phase
error between the reference and feedback of PLL2 is less than the specified time, then the
PLL2 lock counter increments. This value must be programmed to 2 (3.7 ns).
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
Definition
Reserved
Reserved
3.7 ns
6:5
PLL2_WND_SIZE
2
Reserved
This bit programs the PLL2 charge pump output current level. The table below also
illustrates the impact of the PLL2 TRISTATE bit in conjunction with PLL2_CP_GAIN.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
Definition
100 µA
4:3
PLL2_CP_GAIN
3
400 µA
1600 µA
3200 µA
PLL2_CP_POL sets the charge pump polarity for PLL2. The internal VCO requires the
negative charge pump polarity to be selected. Many VCOs use positive slope.
A positive-slope VCO increases output frequency with increasing voltage. A negative-slope
VCO decreases output frequency with increasing voltage.
2
PLL2_CP_POL
0
Field Value
Description
0
1
Negative-slope VCO/VCXO
Positive-slope VCO/VCXO
PLL2_CP_TRI TRI-STATEs the output of the PLL2 charge pump.
1
0
PLL2_CP_TRI
Fixed Value
0
1
0: Disabled
1: TRI-STATE
When programming register 0x169, this field must be set to 1.
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9.7.8.6 SYSREF_REQ_EN, PLL2_DLD_CNT
Table 72. PLL2_DLD_CNT[15:0]
MSB
LSB
0x16A[5:0]
0x16B[7:0]
This register has the value of the PLL2 DLD counter.
Table 73. Registers 0x16A and 0x16B
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
7
6
0x16A
0x16A
NA
0
Reserved
Enables the SYNC/SYSREF_REQ pin to force the SYSREF_MUX = 3 for
continuous pulses. When using this feature, enable the pulser and set
SYSREF_MUX = 2 (pulser).
SYSREF_REQ_EN
0
The reference and feedback of PLL2 must be within the window of phase error,
as specified by PLL2_WND_SIZE for PLL2_DLD_CNT cycles, before PLL2
digital lock detect is asserted.
PLL2_DLD
_CNT[13:8]
5:0
7:0
0x16A
0x16B
32
Field Value
0 (0x00)
Divide Value
Not valid
1 (0x01)
1
2 (0x02)
2
3
3 (0x03)
PLL2_DLD_CNT
0
...
...
16,382 (0x3FFE)
16,383 (0x3FFF)
16,382
16,383
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9.7.8.7 PLL2_LF_R4, PLL2_LF_R3
This register controls the integrated loop filter resistors.
Table 74. Register 0x16C
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:6
NA
0
Reserved
Internal loop filter components are available for PLL2, enabling either 3rd- or 4th-order loop
filters without requiring external components.
Internal loop filter resistor R4 can be set according to the following table.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
Resistance
200 Ω
1 kΩ
5:3
PLL2_LF_R4
0
2 kΩ
4 kΩ
16 kΩ
Reserved
Reserved
Reserved
Internal loop filter components are available for PLL2, enabling either 3rd- or 4th-order loop
filters without requiring external components.
Internal loop filter resistor R3 can be set according to the following table.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
Resistance
200 Ω
1 kΩ
2:0
PLL2_LF_R3
0
2 kΩ
4 kΩ
16 kΩ
Reserved
Reserved
Reserved
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9.7.8.8 PLL2_LF_C4, PLL2_LF_C3
This register controls the integrated loop filter capacitors.
Table 75. Register 0x16D
POR
DEFAULT
BIT
NAME
DESCRIPTION
Internal loop filter components are available for PLL2, enabling either 3rd- or 4th-order loop
filters without requiring external components.
Internal loop filter capacitor C4 can be set according to the following table.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
8 (0x08)
9 (0x09)
10 (0x0A)
11 (0x0B)
12 (0x0C)
13 (0x0D)
14 (0x0E)
15 (0x0F)
Capacitance
10 pF
15 pF
29 pF
34 pF
47 pF
52 pF
7:4
PLL2_LF_C4
0
66 pF
71 pF
103 pF
108 pF
122 pF
126 pF
141 pF
146 pF
Reserved
Reserved
Internal loop filter components are available for PLL2, enabling either 3rd- or 4th-order loop
filters without requiring external components.
Internal loop filter capacitor C3 can be set according to the following table.
Field Value
0 (0x00)
1 (0x01)
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
8 (0x08)
9 (0x09)
10 (0x0A)
11 (0x0B)
12 (0x0C)
13 (0x0D)
14 (0x0E)
15 (0x0F)
Capacitance
10 pF
11 pF
15 pF
16 pF
19 pF
20 pF
3:0
PLL2_LF_C3
0
24 pF
25 pF
29 pF
30 pF
33 pF
34 pF
38 pF
39 pF
Reserved
Reserved
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9.7.8.9 PLL2_LD_MUX, PLL2_LD_TYPE
This register sets the output value of the Status_LD2 pin.
Table 76. Register 0x16E
POR
DEFAULT
BIT
NAME
DESCRIPTION
This sets the output value of the Status_LD2 pin.
Field Value
0 (0x00)
MUX Value
Logic low
1 (0x01)
PLL1 DLD
PLL2 DLD
PLL1 and PLL2 DLD
Holdover status
DAC locked
Reserved
2 (0x02)
3 (0x03)
4 (0x04)
5 (0x05)
6 (0x06)
7 (0x07)
SPI readback
DAC rail
7:3
PLL2_LD_MUX
2
8 (0x08)
9 (0x09)
DAC low
10 (0x0A)
11 (0x0B)
12 (0x0C)
13 (0x0D)
14 (0x0E)
15 (0x0F)
DAC high
PLL1_N
PLL1_N/2
PLL2_N
PLL2_N/2
PLL1_R
16 (0x10)
PLL1_R/2
17 (0x11)
PLL2_R(1)
PLL2_R/2(1)
18 (0x12)
Sets the I/O type of the Status_LD2 pin.
Field Value
0 (0x00)
TYPE
Reserved
1 (0x01)
Reserved
2:0
PLL2_LD_TYPE
6
2 (0x02)
Reserved
3 (0x03)
Output (push-pull)
Output inverted (push-pull)
Reserved
4 (0x04)
5 (0x05)
6 (0x06)
Output (open drain)
(1) Only valid when PLL1_LD_MUX is not set to 2 (PLL2_DLD) or 3 (PLL1 and PLL2 DLD).
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9.7.9 (0x16F - 0x1FFF) Misc Registers
9.7.9.1 PLL2_PRE_PD, PLL2_PD
Table 77. Register 0x173
BIT
NAME
DESCRIPTION
7
N/A
Reserved
Powerdown PLL2 prescaler
0: Normal operation
1: Powerdown
6
PLL2_PRE_PD
Powerdown PLL2
0: Normal operation
1: Powerdown
5
PLL2_PD
N/A
4:0
Reserved
9.7.9.2 VCO1_DIV
Sets the VCO1 VCO divider value. This divider cannot be bypassed, and has a minimum value of 2. This register
is reserved for LMK04826 and LMK04828, and should be left unprogrammed.
Table 78. Register 0x174
POR
DEFAULT
BIT
NAME
DESCRIPTION
7:5
N/A
0
Reserved
When VCO_MUX selects VCO1 for LMK04821, the clock distribution frequency is equal to
VCO1 frequency divided by this divide value. This divider is also on the PLL2 feedback
path, and impacts the PLL2 N divider value.
Unlisted field values are reserved.
Field Value
0 (0x00)
Divide Value
2
3
8
4
5
7
6
VCO1_DIV
(LMK04821 only)
4:0
0
5 (0x05)
10 (0x0A)
20 (0x14)
23 (0x17)
27 (0x1B)
30 (0x1E)
9.7.9.3 OPT_REG_1
This register must be written with the following value, depending on which LMK0482x family part is used to
optimize VCO1 phase-noise performance over temperature. This register must be written before writing register
0x168 when using VCO1.
Table 79. Register 0x17C
BIT
NAME
DESCRIPTION
21: LMK04821
24: LMK04826
21: LMK04828
7:0
OPT_REG_1
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9.7.9.4 OPT_REG_2
This register must be written with the following value, depending on which LMK0482x family part is used to
optimize VCO1 phase-noise performance over temperature. This register must be written before writing register
0x168 when using VCO1.
Table 80. Register 0x17D
BIT
NAME
DESCRIPTION
51: LMK04821
119: LMK04826
51: LMK04828
7:0
OPT_REG_2
9.7.9.5 RB_PLL1_LD_LOST, RB_PLL1_LD, CLR_PLL1_LD_LOST
Table 81. Register 0x182
BIT
7:3
2
NAME
N/A
DESCRIPTION
Reserved
RB_PLL1_LD_LOST
This is set when PLL1 DLD edge falls. Does not set if cleared while PLL1 DLD is low.
Read back 0: PLL1 DLD is low.
Read back 1: PLL1 DLD is high.
1
RB_PLL1_LD
To reset RB_PLL1_LD_LOST, write CLR_PLL1_LD_LOST with 1 and then 0.
0: RB_PLL1_LD_LOST is set on next falling PLL1 DLD edge.
1: RB_PLL1_LD_LOST is held clear (0). User must clear this bit to allow RB_PLL1_LD_LOST to
become set again.
0
CLR_PLL1_LD_LOST
9.7.9.6 RB_PLL2_LD_LOST, RB_PLL2_LD, CLR_PLL2_LD_LOST
Table 82. Register 0x0x183
BIT
7:3
2
NAME
N/A
DESCRIPTION
Reserved
RB_PLL2_LD_LOST
This is set when PLL2 DLD edge falls. Does not set if cleared while PLL2 DLD is low.
PLL1_LD_MUX or PLL2_LD_MUX must select setting 2 (PLL2 DLD) for valid reading of this bit.
Read back 0: PLL2 DLD is low.
1
RB_PLL2_LD
Read back 1: PLL2 DLD is high.
To reset RB_PLL2_LD_LOST, write CLR_PLL2_LD_LOST with 1 and then 0.
0: RB_PLL2_LD_LOST is set on next falling PLL2 DLD edge.
1: RB_PLL2_LD_LOST is held clear (0). User must clear this bit to allow RB_PLL2_LD_LOST to
become set again.
0
CLR_PLL2_LD_LOST
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9.7.9.7 RB_DAC_VALUE(MSB), RB_CLKinX_SEL, RB_CLKinX_LOS
This register provides read back access to CLKinX selection indicator and CLKinX LOS indicator. The 2 MSBs
are shared with the RB_DAC_VALUE. See RB_DAC_VALUE section.
Table 83. Register 0x184
BIT
NAME
DESCRIPTION
7:6
RB_DAC_VALUE[9:8] See RB_DAC_VALUE section.
Read back 0: CLKin2 is not selected for input to PLL1.
Read back 1: CLKin2 is selected for input to PLL1.
5
4
RB_CLKin2_SEL
RB_CLKin1_SEL
Read back 0: CLKin1 is not selected for input to PLL1.
Read back 1: CLKin1 is selected for input to PLL1.
Read back 0: CLKin0 is not selected for input to PLL1.
Read back 1: CLKin0 is selected for input to PLL1.
3
2
1
RB_CLKin0_SEL
N/A
Read back 1: CLKin1 LOS is active.
Read back 0: CLKin1 LOS is not active.
RB_CLKin1_LOS
Read back 1: CLKin0 LOS is active.
Read back 0: CLKin0 LOS is not active.
0
RB_CLKin0_LOS
9.7.9.8 RB_DAC_VALUE
Contains the value of the DAC for user readback.
FIELD NAME
MSB
LSB
RB_DAC_VALUE
0x184 [7:6]
0x185 [7:0]
Table 84. Registers 0x184 and 0x185
POR
DEFAULT
BIT REGISTERS
NAME
DESCRIPTION
RB_DAC_
VALUE[9:8]
DAC value is 512 on power-on reset; if PLL1 locks upon power-up, the DAC
value changes.
7:6
7:0
0x184
0x185
2
RB_DAC_
VALUE[7:0]
0
9.7.9.9 RB_HOLDOVER
Table 85. Register 0x188
BIT
NAME
DESCRIPTION
7:5
N/A
Reserved
Read back 0: Not in HOLDOVER
Read back 1: In HOLDOVER
4
RB_HOLDOVER
N/A
3:0
Reserved
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9.7.9.10 SPI_LOCK
Prevents SPI registers from being written to, except for 0x1FFD, 0x1FFE, and 0x1FFF. These registers must be
written to sequentially and in order: 0x1FFD, 0x1FFE, 0x1FFF.
These registers cannot be read back.
MSB
—
LSB
0x1FFD [7:0]
0x1FFE [7:0]
0x1FFF [7:0]
Table 86. Registers 0x1FFD, 0x1FFE, and 0x1FFF
POR
BIT REGISTERS
NAME
DESCRIPTION
DEFAULT
0: Registers unlocked.
1 to 255: Registers locked
7:0
7:0
0x1FFD
0x1FFE
SPI_LOCK[23:16]
SPI_LOCK[15:8]
0
0
0: Registers unlocked.
1 to 255: Registers locked
0 to 82: Registers locked
83: Registers unlocked
84 to 256: Registers locked
7:0
0x1FFF
SPI_LOCK[7:0]
83
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10 Applications and Implementation
10.1 Application Information
To assist customers in frequency planning and designing loop filters, Texas Instruments provides PLLatinum Sim
(www.ti.com/tool/PLLATINUMSIM-SW) and TICS Pro (www.ti.com/tool/TICSPRO-SW).
10.2 Digital Lock Detect Frequency Accuracy
The digital lock detect circuit is used to determine PLL1 locked, PLL2 locked, and holdover exit events. A window
size and lock count register are programmed to set a ppm frequency accuracy of reference to feedback signals
of the PLL, for each event to occur. When a PLL digital lock event occurs, the PLL digital lock detect is asserted
true. When the holdover exit event occurs, the device exits holdover mode.
EVENT
PLL
PLL1
PLL2
PLL1
WINDOW SIZE
PLL1_WND_SIZE
PLL2_WND_SIZE
PLL1_WND_SIZE
LOCK COUNT
PLL1_DLD_CNT
PLL1 locked
PLL2 locked
Holdover exit
PLL2_DLD_CNT
HOLDOVER_DLD_CNT
For a digital lock detect event to occur, there must be a “lock count” number of phase-detector cycles of PLLX,
during which the time/phase error of the PLLX_R reference and PLLX_N feedback signal edges are within the
user programmable "window size." Because there must be at least "lock count" phase-detector events before a
lock event occurs, a minimum digital lock event time can be calculated as "lock count" / fPDX, where X = 1 for
PLL1 or 2 for PLL2.
By using Equation 6, values for a "lock count" and "window size" can be chosen to set the frequency accuracy
required by the system in ppm before the digital lock detect event occurs:
1e6 × PLLX_WND_SIZE × fPDX
ppm =
PLLX_DLD_CNT
(6)
The effect of the "lock count" value is that it shortens the effective lock window size by dividing the "window size"
by "lock count".
If at any time the PLLX_R reference and PLLX_N feedback signals are outside the time window set by "window
size", then the “lock count” value is reset to 0.
10.2.1 Minimum Lock Time Calculation Example
To calculate the minimum PLL2 digital lock time given a PLL2 phase-detector frequency of 40 MHz and
PLL2_DLD_CNT = 10,000: the minimum lock time of PLL2 is 10,000 / 40 MHz = 250 µs.
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10.3 Driving CLKin and OSCin Inputs
10.3.1 Driving CLKin and OSCin Pins With a Differential Source
Both CLKin ports can be driven by differential signals. TI recommends that the CLKin input mode be set to
bipolar (CLKinX_TYPE = 0) when using differential reference clocks. The OSCin input mode is hard-wired to
bipolar-equivalent. The LMK0482x family internally biases the input pins, thus the differential interface should be
AC coupled. The recommended circuits for driving the CLKin/OSCin pins with either LVDS or LVPECL are
shown in Figure 24 and Figure 25.
Figure 24. CLKinX and OSCin Termination for an LVDS Reference Clock Source
Figure 25. CLKinX and OSCin Termination for an LVPECL Reference Clock Source
A reference clock source that produces a differential sine wave output can drive the CLKin/OSCin pins using the
following circuit. The signal level must conform to the requirements for the CLKin/OSCin pins listed in Electrical
Characteristics.
Figure 26. CLKinX and OSCin Termination for a Differential Sinewave Reference Clock Source
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Driving CLKin and OSCin Inputs (continued)
10.3.2 Driving CLKin and OSCin Pins With a Single-Ended Source
The CLKin/OSCin pins of the LMK0482x family can be driven using a single-ended reference clock source; for
example, either a sine wave source or an LVCMOS/LVTTL source. For the CLKin pins, either AC coupling or DC
coupling may be used. For the OSCin pins, AC coupling is required. In the case of the sine wave source that is
expecting a 50-Ω load, TI recommends using AC coupling, as shown in the circuit below with a 50-Ω termination.
NOTE
The signal level must conform to the requirements for the CLKin/OSCin pins listed in
Electrical Characteristics. CLKinX_TYPE is recommended to be set to bipolar mode
(CLKinX_TYPE = 0). OSCin is hard-wired to bipolar mode.
Figure 27. CLKinX and OSCin Single-Ended Termination
If the CLKin pins are being driven with a single-ended LVCMOS/LVTTL source, either DC coupling or AC
coupling may be used. If DC coupling is used, the CLKinX_TYPE should be set to MOS buffer mode
(CLKinX_TYPE = 1), and the voltage swing of the source must meet the specifications for DC-coupled, MOS-
mode clock inputs given in Electrical Characteristics. If AC coupling is used, the CLKinX_TYPE should be set to
the bipolar buffer mode (CLKinX_TYPE = 0), and the voltage swing at the input pins must meet the specifications
for AC-coupled, bipolar-mode clock inputs given in Electrical Characteristics. In AC-coupled bipolar mode, some
attenuation of the clock input level may be required. A simple resistive divider circuit before the AC coupling
capacitor is sufficient.
Figure 28. DC-Coupled LVCMOS/LVTTL Reference Clock
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10.4 Output Termination and Biasing
10.4.1 LVPECL
Figure 29 shows the recommended resistor biasing configuration for the LVPECL format for both CLKout and
OSCout pins. The LVPECL emitter resistors for DCLKoutX or SDCLKoutY can be selected such that 120 Ω ≤ Re
≤ 240 Ω. When OSCout (pins 40 and 41) are configured to provide a buffered oscillator output in LVPECL
format, TI recommends setting the value of the emitter resistors for OSCout to 240 Ω. To avoid bias mismatch or
excessive loading of the bias circuitry, TI recommends connecting LVPECL outputs to the load through AC-
coupling capacitors as shown.
Figure 29. LVPECL Biasing for CLKout and OSCout
10.4.2 LVDS/HSDS
Figure 30 shows the recommended resistor biasing configuration for the LVDS/HSDS format for both CLKout
and OSCout pins. When connecting an HSDS output to a load, it should be AC-coupled. In cases where the
common mode output voltage of the LMK0482x family LVDS matches the common mode input voltage of the
LVDS receiver, DC coupling can be used; however, frequently LVDS is also AC-coupled to avoid any
driver/receiver mismatch issues.
The LVDS/HSDS driver requires a DC path for current from CLKoutX to CLKoutX* and from OSCout to OSCout*
on initial startup. If a DC path for current is not present on startup, LVDS/HSDS outputs may start up with lower
amplitude than expected, and in some cases could generate runt pulses or fail to oscillate for some time after
startup. Whenever AC-coupled LVDS or HSDS is used with external termination, the 100-Ω termination should
be placed on the LMK0482x side of the AC-coupling capacitors as illustrated in Figure 30.
Figure 30. LVDS/HSDS Output Termination for OSCout and CLKout, External Receiver Termination
In cases where the termination is internal to the receiver, place 560 Ω close to the CLKoutX/X* or
OSCout/OSCout* pins, to provide a DC path for the output on startup as illustrated in Figure 31.
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Output Termination and Biasing (continued)
Figure 31. LVDS/HSDS Output Termination for OSCout and CLKout, Internal Receiver Termination
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10.5 Typical Applications
10.5.1 Design Example
This design example below highlights using the available tools to design loop filters and create a programming
map for the LMK0482x.
10.5.1.1 Design Requirements
Clocks outputs:
•
1x 245.76-MHz clock for JESD204B ADC, LVPECL.
This clock requires the best performance in this example.
–
•
•
•
•
2x 983.04-MHz clock for JESD204B DAC, LVPECL.
1x 122.88-MHz clock for JESD204B FPGA block, LVDS
4x 10.24-MHz SYSREF for ADC (LCPECL), DAC (LVPECL), FPGA (LVDS).
2x 122.88-MHz clock for FPGA, LVDS
For best performance, the highest possible phase detector frequency is used at PLL2. As such, a 122.88-MHz
VCXO is used.
10.5.1.2 Detailed Design Procedure
This information is current as of the date of the release of this data sheet. Design tools receive continuous
improvements to add features and improve model accuracy. Refer to the software instructions or training for the
latest features.
10.5.1.2.1 Device Configuration and Simulation - PLLatinum Sim
Select the LMK04828 and choose the PLL and VCO to simulate. Make adjustments for more accurate
simulations depending on the application. For example:
•
•
Enter the VCO gain of the external VCXO or possible external VCO-used device.
Adjust the charge pump current to help with loop filter component selection. Lower charge pump currents
result in smaller components, but may increase impacts of leakage, and at the lowest values reduce PLL
phase-noise performance.
•
•
PLLatinum Sim allows loading a custom phase noise plot for any block. Typically, a custom phase-noise plot
is entered for CLKin to match the reference phase noise to device; a phase-noise plot for the VCXO can
additionally be provided to match the performance of VCXO used. For improved accuracy in simulation and
optimum loop filter design, load these custom noise profiles for use in the application.
The design tools return with high reference and phase-detector frequencies by default. If desired, experiment
with different reference divider settings, phase detector frequencies, and loop bandwidths. Due to the narrow
loop bandwidth used on PLL1, it is common to reduce the phase detector frequency on PLL1.
10.5.1.2.2 Device Programming
Using the PLLatinum Sim configuration, the TICS Pro software is manually updated with this information to meet
the required application. For the JESD204B outputs, place the device clocks on the DCLKoutX output, then turn
on the paired SDCLKoutY output for SYSREF output. For non-JESD204B outputs, both DCLKoutX and paired
SDCLKoutY may be driven by the device clock divider to maximize number of available outputs.
Frequency planning for assignment of outputs:
•
To minimize crosstalk, perform frequency planning / CLKout assignments to keep common frequencies on
outputs close together.
•
It is best to place common device clock output frequencies on outputs sharing the same Vcc group. For
example, these outputs share Vcc4_CG2. Refer to Pin Configuration and Functions to see the Vcc groupings
the clock outputs.
In this example, the 245.76-MHz ADC output requires the best performance. DCLKout2 on the LMK0482x
provides the best noise floor / performance. The 245.76 MHz is placed on DCLKout2 with 10.24-MHz SYSREF
on SDCLKout3.
•
For best performance, the input and output drive level bits may be set. Best noise floor performance is
achieved with CLKout2_IDL = 1 and CLKout2_ODL = 1.
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Typical Applications (continued)
In this example, the 983.04-MHz DAC output is placed on DCLKout4 and DCLKout6, with 10.24-MHz SYSREF
on paired SDCLKout5 and SDCLKout7 outputs.
•
These outputs share Vcc4_CG2.
In this example, the 122.88-MHz FPGA JESD204B output is placed on DCLKout10, with 10.24-MHz SYSREF on
paired SDCLKout11 output.
Additionally, the 122.88-MHz FPGA non-JESD204B outputs are placed on DCLKout8 and SDCLKout9.
•
When frequency planning, consider PLL2 as a clock output at the phase-detector frequency. As such, these
122.88-MHz outputs have been placed on the outputs close to the PLL2 and charge pump power supplies.
The register programming can be validated live on the device, with a SPI header wired to a TI USB2ANY
programmer. When the device programming is completed as desired in the TICS Pro software, it is possible to
export the register settings by using the Export Hex Registers option in the file menu.
10.5.1.3 Application Curves
Figure 32. DCLKout0, 245.76-MHz
LVPECL20 With 240-Ω Emitter Resistors
CLKout0_1_IDL = 1, CLKout0_1_ODL = 1
Figure 33. DCLKout2, 245.76-MHz
LVPECL20 With 240-Ω Emitter Resistors
CLKout2_3_IDL = 1, CLKout2_3_ODL = 1
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Typical Applications (continued)
Figure 34. DCLKout4, 983.04-MHz
LVPECL16 With 240-Ω Emitter Resistors
CLKout4_5_IDL = 1, CLKout4_5_ODL = 0
Figure 35. DCLKout6, 983.04-MHz
LVPECL16 With 240-Ω Emitter Resistors
CLKout6_7_IDL = 1, CLKout6_7_ODL = 0
Figure 36. DCLKout10, 122.88 MHz, LVDS
CLKout10_11_IDL = 1, CLKout10_11_ODL = 0
Figure 37. SDCLKout11, 122.88 MHz, LVDS
CLKout10_11_IDL = 1, CLKout10_11_ODL = 0
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Typical Applications (continued)
Figure 38. OSCout, 122.88 MHz, LVCMOS (Norm/Inv)
Normal Output Measured, Inverse 50-Ω Termination
Figure 39. Direct VCXO Measurement
Open Loop, Holdover Mode Set
10.6 System Examples
10.6.1 System Level Diagram
Figure 40 and Figure 41 show an LMK0482x family device with external circuitry for clocking and for power
supply to serve as a guideline for good practices when designing with the LMK0482x family. Refer to Pin
Connection Recommendations for more details on the pin connections and bypassing recommendations. Also
refer to the evaluation board in LMK04826/28 User's Guide. PCB design will also play a role in device
performance.
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System Examples (continued)
Figure 40. Example Application - System Schematic Except for Power
Figure 40 shows the primary reference clock input is at CLKin0/0*. A secondary reference clock is driving
CLKin1/1*. Both clocks are depicted as AC-coupled drivers. The VCXO attached to the OSCin/OSCin* port is
configured as an AC-coupled single-ended driver. Any of the input ports (CLKin0/0*, CLKin1/1*, CLKin2/2*,
OSCin/OSCin*) may be configured as either differential or single-ended (see Driving CLKin and OSCin Inputs).
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System Examples (continued)
The loop filter for PLL1 is configured as a 2nd-order passive filter, while the loop filter for PLL2 is configured as a
4th order passive filter (using internal 3rd and 4th order components). Typically it is not necessary to increase the
filter beyond 2nd order for PLL1. PLL2 allows software programmability of the 3rd and 4th order components
(see PLL2 Integrated Loop Filter Poles). PLLatinum Sim can be used to compute the loop filter values for optimal
phase noise.
All the LVPECL clock outputs are AC-coupled with 0.1 µF capacitors. Some LVPECL outputs are depicted with
240-Ω emitter resistors, and some are depicted with 150-Ω emitter resistors. LVPECL clock outputs can use
emitter resistors between 120 Ω and 240 Ω. OSCout LVPECL format only supports 240-Ω emitter resistors is
depicted with 240-Ω emitter resistors. The LCPECL SYSREF output is DC-coupled, with termination values
matching the conditions specified for LCPECL in the Electrical Characteristics. The non-JESD204B LVDS
outputs are AC-coupled, and include 560 Ω between the pins of the differential pair to create a DC path for
current on startup (see LVDS/HSDS). The JESD204B LVDS outputs are DC-coupled. Unused outputs are left
floating.
PCB design will influence crosstalk performance. Tightly coupled clock traces will have less crosstalk than
loosely coupled clock traces. Proximity to other clock traces will influence crosstalk.
Figure 41. Example Application - Power System Schematic
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System Examples (continued)
Figure 41 shows an example decoupling and bypassing scheme for the LMK0482x, which could apply to the
configuration shown in Figure 40. Components drawn in dotted lines are optional (see Pin Connection
Recommendations). Two power planes are used in these example designs, one for the clock outputs and one for
the PLL circuits. It is possible to reduce the number of decoupling components by tying together clock output Vcc
pins for CLKouts that share the same frequency or otherwise can tolerate potential crosstalk between outputs
with different frequencies. In the two examples, Vcc2 and Vcc11 can be tied together since no outputs are
utilized from Clock Group 0. PCB design will influence impedance to the supply. Vias and traces will increase the
impedance to the power supply. Ensure good direct return current paths.
10.7 Do's and Don'ts
•
•
•
•
VCC Pins and Decoupling: all VCC pins must always be connected.
Unused Clock Outputs: leave unused clock outputs floating and powered down.
Unused Clock Inputs: unused clock inputs can be left floating.
OSCout: When set to an LVPECL drive format, OSCout emitter resistors should be 240 Ω to GND.
Otherwise, OSCout may be treated like any other clock output.
•
•
LVDS/HSDS Outputs: Ensure that there is a DC path for current from CLKoutX to CLKoutX*, and from
OSCout to OSCout*, for all LVDS/HSDS outputs at startup. See LVDS/HSDS.
RESET Pin: If the RESET pin is used, place a capacitor on RESET pin to prevent external noise from
causing device reset. If reset functionality is not used, consider resetting GPIO as output to prevent external
noise from causing device reset.
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11 Power Supply Recommendations
11.1 Pin Connection Recommendations
11.1.1 VCC Pins and Decoupling
All Vcc pins must always be connected.
Integrated capacitance on the LMK0482x makes external high frequency decoupling capacitors (<1 nF)
unnecessary. The internal capacitance is more effective at filtering high frequency noise than off-device bypass
capacitance because there is no bond wire inductance between the LMK0482x circuit and the bypass capacitor.
For lower-frequency decoupling and voltage stabilization, decoupling capacitors are still beneficial.
11.1.1.1 Clock Output Supplies
These supplies include Vcc2_CG1, Vcc3_SYSREF, Vcc4_CG2, Vcc11_CG3, and Vcc12_CG0. If OSCout is
used, Vcc7_OSCout can also be considered a clock output supply.
Ferrite beads may be used to reduce crosstalk between different clock groups on the same LMK0482x device.
Ferrite beads placed between the power supply and a clock group Vcc pin should reduce noise between the Vcc
pin and the power supply modestly above 30 MHz. Below 30 MHz, integrated LDOs provide additional noise
mitigation. When two clock groups share the same frequency, or if a clock group is not used, a single ferrite bead
can be used between the power supply and each same-frequency clock group Vcc pin.
When using ferrite beads on clock group Vcc pins, consider the following guidelines to ensure the power supply
will source the needed switching current:
•
In cases with an output frequency > 30 MHz, a ferrite bead may be placed and the internal capacitance is
sufficient
•
If a ferrite bead is used with a low frequency output (< 30 MHz), and the output format is set to a high current
switching format such as LVPECL or LCPECL, then:
–
The ferrite bead can be removed to lower the impedance to the main power supply and bypass capacitors,
or
–
Localized capacitance can be placed between the ferrite bead and Vcc pin to support the switching
current.
–
Note: the decoupling capacitors used between the ferrite bead and a clock group Vcc pin can permit
high frequency switching noise to couple through the capacitors into the ground plane and onto other
clock VCC pins through their decoupling capacitors. Placing unnecessary decoupling capacitances, or
placing ferrite beads with excessive impedance at high frequency (> 200 Ω) can degrade crosstalk
performance.
–
If the OSCout buffer format is LVCMOS, TI recommends using a complementary output format such as
LVCMOS (Norm/Inv) to reduce switching noise and crosstalk. If only a single LVCMOS output is required,
the complementary LVCMOS output format can still be used by leaving the unused LVCMOS output
floating.
•
Vcc3_SYSREF powers both the SYSREF divider and the SYNC circuitry. If SYNC is used but the SYSREF
divider is not, Vcc3_SYSREF can be connected to any other clock output supply without impacting noise
performance.
11.1.1.2 Low-Crosstalk Supplies
These supplies include Vcc1_VCO, Vcc5_DIG, and Vcc6_PLL1.
Each of these pins has internal bypass capacitance. Ferrite beads should not be needed between these pins and
the power supply. A ferrite bead can optionally before the common point connecting these supplies, in which
case a large decoupling capacitance (1 µF or more) should be used for voltage stability after the ferrite bead.
The typical application diagram in Figure 41 shows all these supply pins connected together to the power supply
with an optional ferrite bead and decoupling capacitance.
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Pin Connection Recommendations (continued)
These supplies are considered low-crosstalk supplies because they do not generate much noise. Vcc1_VCO
noise is effectively captured by the on-chip bypass capacitance, since noise from this pin is typically very high
frequency. This pin also uses a high-quality integrated LDO to minimize noise below 30 MHz. Vcc5_DIG is only
active at startup and during GPIO events, so after startup there is no continuous noise contribution from this pin.
Vcc6_PLL1 is usually low-noise as well, due to the low frequency of the PLL1 phase detector. An on-chip LDO
regulates this supply and prevents most PLL1 charge pump noise from escaping. If the PLL1 phase detector is
set to a high frequency, a ferrite bead may optionally be used on this supply. If a ferrite bead is used with this
supply, the DC resistance of this ferrite bead should be minimized to avoid voltage fluctuation at the PLL1
supply/PLL1 charge pump, and a 0.1-µF decoupling capacitor should be placed after the ferrite bead close to the
supply pin.
11.1.1.3 PLL2 Supplies
These supplies include Vcc9_CP2 and Vcc10_PLL2.
Each of these pins has an internal bypass capacitor. A ferrite bead should be placed between the power supply
and Vcc9. The DC resistance of this ferrite bead should be minimized to avoid voltage fluctuations at the PLL2
charge pump. Typically the frequency of the PLL2 phase detector is >50 MHz and an external decoupling
capacitor is not necessary. For lower PLL2 phase detector frequencies, a 0.1-µF decoupling capacitor should be
placed after the ferrite bead close to the supply pin. Use of a ferrite bead between the power supply and
Vcc10_PLL2 is optional. Normally the frequency of the dividers used by PLL2 is high enough that all noise is
well-constrained by the on-chip bypass capacitance. If a ferrite bead is used, a 0.1-µF decoupling capacitor
should be placed after the ferrite bead close to the supply pin.
11.1.1.4 Clock Input Supplies
These supplies include Vcc6_PLL1 and Vcc9_OSCin. If CLKin2 is used, Vcc7_OSCout is also included.
For Vcc6_PLL1, follow guidance in Low-Crosstalk Supplies. For Vcc9_OSCin, a ferrite bead is recommended for
VCXO frequencies above 30 MHz. Typically above 100 MHz no bypass capacitance is necessary on this pin, but
if the OSCin frequency is < 100 MHz, a 0.1-µF decoupling capacitor should be placed after the ferrite bead close
to the supply pin. Vcc7_OSCout should follow similar guidance to Vcc9 for CLKin2 above 30 MHz, and
Vcc6_PLL1 for CLKin2 below 30 MHz.
When CLKin1 is used as Fin or FBCLKin, TI recommends using CLKin2 as the source to PLL1 whenever
possible. CLKin0 and CLKin1 share Vcc6_PLL1 supply, and in cases where Fin or FBCLKin is high frequency,
CLKin0 can crosstalk to Fin/FBCLKin through Vcc6_PLL1. CLKin2 is powered from Vcc7_OSCout, and the
crosstalk between Fin/FBCLKin and CLKin2 is significantly reduced as a result.
11.1.1.5 Unused Clock Inputs/Outputs
Leave unused clock inputs and outputs floating. Set unused clock outputs to powerdown format, and disable
unused channel pairs. If the SYSREF is not used in a channel pair, SDCLKoutY_PD can be set. For maximum
power savings and noise immunity, set DCLKoutX_PD, SDCLKoutY_PD, and CLKoutX_Y_PD on all unused
channel pairs.
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11.2 Current Consumption / Power Dissipation Calculations
From Table 87, the current consumption can be calculated for any configuration. The data below is typical and
not assured.
The TICS Pro device profiles for LMK0482x family devices also include a current calculator, which performs real-
time analysis of the register settings and estimates the current consumption based on which blocks are enabled.
TI strongly recommends using TICS Pro to compute the current for any device profile, as it is faster and more
flexible than manual computation using the table below. TICS Pro does not require a connection to the
LMK0482x to generate a current consumption estimate or a register file.
Table 87. Typical Current Consumption for Selected Functional Blocks
(TA = 25 °C, VCC = 3.3 V)
POWER
TYPICAL ICC
(mA)
DISSIPATED
in DEVICE
(mW)
BLOCK
CONDITION
CORE and FUNCTIONAL BLOCKS
Core
Dual loop, internal VCO0
VCO1 is selected
PLL1 and PLL2 locked
131.5
13.5
22
433.95
44.55
72.6
LMK04826/LMK04828
LMK04821
VCO (with VCO divider for
LMK04821)
OSCin Doubler
CLKin
Doubler is enabled
EN_PLL2_REF_2X = 1
3
9.9
Any one of the CLKinX is enabled
4.9
1.3
16.17
4.29
Holdover is enabled
Hitless switch is enabled
Track mode
HOLDOVER_EN = 1
HOLDOVER_HITLESS_SWI
TCH = 1
Holdover
0.9
2.97
TRACK_EN = 1
2.5
7.6
8.25
25.08
89.76
SYNC_EN = 1
Required for SYNC and SYSREF functionality
Enabled
SYSREF_PD = 0
27.2
Dynamic digital delay
enabled
SYSREF_DDLY_PD = 0
5
16.5
SYSREF
Pulser is enabled
SYSREF_PLSR_PD = 0
SYSREF_MUX = 2
SYSREF_MUX = 3
4.1
3
13.53
9.9
SYSREF pulses mode
SYSREF continuous mode
3
9.9
CLOCK GROUP
Enabled
IDL
Any one of the CLKoutX_Y_PD = 0
Any one of the CLKoutX_Y_IDL = 1
Andy one of the CLKoutX_Y_ODL = 1
20.1
2.2
66.33
7.26
ODL
3.2
10.56
44.88
58.41
44.88
Divider only
DCLKoutX_MUX = 0
13.6
17.7
13.6
Clock Divider
Divider + DCC + HS
Analog delay + divider
DCLKoutX_MUX = 1
DCLKoutX_MUX = 3
CLOCK OUTPUT BUFFERS
LVDS
100-Ω differential termination
6
19.8
29.04
38.28
64.02
HSDS 6 mA, 100-Ω differential termination
HSDS 8 mA, 100-Ω differential termination
HSDS 10 mA, 100-Ω differential termination
8.8
HSDS
11.6
19.4
OSCout BUFFERS
LVDS
100-Ω differential termination
18.5
42.6
27
61.05
140.58
89.1
LVCMOS pair
150 MHz
150 MHz
LVCMOS
LVCMOS single
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12 Layout
12.1 Layout Guidelines
12.1.1 Thermal Management
Power consumption of the LMK0482x family of devices can be high enough to require attention to thermal
management. For reliability and performance reasons, the die temperature should be limited to a maximum of
125°C. That is, as an estimate, TA (ambient temperature) plus device power consumption multiplied by RθJA
should not exceed 125°C.
The package of the device has an exposed pad that provides the primary heat removal path, as well as excellent
electrical grounding to a printed circuit board. To maximize the removal of heat from the package, a thermal land
pattern, including multiple vias to a ground plane, must be incorporated on the PCB within the footprint of the
package. The exposed pad must be soldered down to ensure adequate heat conduction out of the package.
7.2 mm
0.2 mm
1.46 mm
1.15 mm
Figure 42. Recommended Land and Via Pattern
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12.2 Layout Example
Figure 43. LMK0482x Layout Example
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13 Device and Documentation Support
13.1 Device Support
13.1.1 Development Support
13.1.1.1 PLLatinum Sim
Loop filter design and simulation.
For PLLatinum Sim, go to www.ti.com/tool/PLLATINUMSIM-SW.
13.1.1.2 TICS Pro
EVM programming software. Can also be used to generate register map for programming for a specific
application.
For TICS Pro, go to www.ti.com/tool/TICSPRO-SW
13.2 Related Links
The table below lists quick access links. Categories include technical documents, support and community
resources, tools and software, and quick access to sample or buy.
Table 88. Related Links
TECHNICAL
DOCUMENTS
TOOLS &
SOFTWARE
SUPPORT &
COMMUNITY
PARTS
PRODUCT FOLDER
SAMPLE & BUY
LMK04821
LMK04826
LMK04828
Click here
Click here
Click here
Click here
Click here
Click here
Click here
Click here
Click here
Click here
Click here
Click here
Click here
Click here
Click here
13.3 Trademarks
PLLatinum is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
13.4 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
13.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
14 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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Product Folder Links: LMK04821 LMK04826 LMK04828
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status Package Type Package Pins Package
Eco Plan
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
Samples
Drawing
Qty
(1)
(2)
(3)
(4/5)
(6)
LMK04821NKDR
LMK04821NKDT
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
WQFN
WQFN
WQFN
WQFN
WQFN
WQFN
WQFN
WQFN
NKD
NKD
NKD
NKD
NKD
NKD
NKD
NKD
64
64
64
64
64
64
64
64
1000 RoHS & Green
250 RoHS & Green
1000 RoHS & Green
250 RoHS & Green
SN
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
-40 to 85
-40 to 85
-40 to 85
-40 to 85
-40 to 85
-40 to 85
-40 to 85
-40 to 85
K04821NKD
SN
SN
SN
SN
SN
SN
SN
K04821NKD
K04826BISQ
K04826BISQ
K04826BISQ
K04828BISQ
K04828BISQ
K04828BISQ
LMK04826BISQ/NOPB
LMK04826BISQE/NOPB
LMK04826BISQX/NOPB
LMK04828BISQ/NOPB
LMK04828BISQE/NOPB
LMK04828BISQX/NOPB
2000 RoHS & Green
1000 RoHS & Green
250
RoHS & Green
2000 RoHS & Green
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based
flame retardants must also meet the <=1000ppm threshold requirement.
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
(6)
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two
lines if the finish value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
OTHER QUALIFIED VERSIONS OF LMK04828 :
Enhanced Product: LMK04828-EP
•
NOTE: Qualified Version Definitions:
Enhanced Product - Supports Defense, Aerospace and Medical Applications
•
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
24-Jun-2023
TAPE AND REEL INFORMATION
REEL DIMENSIONS
TAPE DIMENSIONS
K0
P1
W
B0
Reel
Diameter
Cavity
A0
A0 Dimension designed to accommodate the component width
B0 Dimension designed to accommodate the component length
K0 Dimension designed to accommodate the component thickness
Overall width of the carrier tape
W
P1 Pitch between successive cavity centers
Reel Width (W1)
QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE
Sprocket Holes
Q1 Q2
Q3 Q4
Q1 Q2
Q3 Q4
User Direction of Feed
Pocket Quadrants
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
B0
K0
P1
W
Pin1
Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant
(mm) W1 (mm)
LMK04821NKDR
LMK04821NKDT
WQFN
WQFN
WQFN
NKD
NKD
NKD
NKD
NKD
NKD
NKD
NKD
64
64
64
64
64
64
64
64
1000
250
330.0
178.0
330.0
178.0
330.0
330.0
178.0
330.0
16.4
16.4
16.4
16.4
16.4
16.4
16.4
16.4
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
16.0
16.0
16.0
16.0
16.0
16.0
16.0
16.0
Q1
Q1
Q1
Q1
Q1
Q1
Q1
Q1
LMK04826BISQ/NOPB
1000
250
LMK04826BISQE/NOPB WQFN
LMK04826BISQX/NOPB WQFN
2000
1000
250
LMK04828BISQ/NOPB
WQFN
LMK04828BISQE/NOPB WQFN
LMK04828BISQX/NOPB WQFN
2000
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
24-Jun-2023
TAPE AND REEL BOX DIMENSIONS
Width (mm)
H
W
L
*All dimensions are nominal
Device
Package Type Package Drawing Pins
SPQ
Length (mm) Width (mm) Height (mm)
LMK04821NKDR
LMK04821NKDT
WQFN
WQFN
WQFN
WQFN
WQFN
WQFN
WQFN
WQFN
NKD
NKD
NKD
NKD
NKD
NKD
NKD
NKD
64
64
64
64
64
64
64
64
1000
250
356.0
208.0
356.0
208.0
356.0
356.0
208.0
356.0
356.0
191.0
356.0
191.0
356.0
356.0
191.0
356.0
35.0
35.0
35.0
35.0
35.0
35.0
35.0
35.0
LMK04826BISQ/NOPB
LMK04826BISQE/NOPB
LMK04826BISQX/NOPB
LMK04828BISQ/NOPB
LMK04828BISQE/NOPB
LMK04828BISQX/NOPB
1000
250
2000
1000
250
2000
Pack Materials-Page 2
GENERIC PACKAGE VIEW
NKD 64
9 x 9, 0.5 mm pitch
WQFN - 0.8 mm max height
PLASTIC QUAD FLATPACK - NO LEAD
This image is a representation of the package family, actual package may vary.
Refer to the product data sheet for package details.
4229637/A
www.ti.com
PACKAGE OUTLINE
NKD0064A
WQFN - 0.8 mm max height
S
C
A
L
E
1
.
6
0
0
WQFN
9.1
8.9
A
B
PIN 1 INDEX AREA
0.5
0.3
9.1
8.9
0.3
0.2
DETAIL
OPTIONAL TERMINAL
TYPICAL
0.8 MAX
C
SEATING PLANE
(0.1)
TYP
7.2 0.1
SEE TERMINAL
DETAIL
17
32
60X 0.5
33
16
4X
7.5
1
48
0.3
64X
PIN 1 ID
64
49
0.2
(OPTIONAL)
0.1
C A
C
B
0.5
0.3
64X
0.05
4214996/A 08/2013
NOTES:
1. All linear dimensions are in millimeters. Dimensions in parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance.
www.ti.com
EXAMPLE BOARD LAYOUT
NKD0064A
WQFN - 0.8 mm max height
WQFN
(
7.2)
SYMM
64X (0.6)
64X (0.25)
SEE DETAILS
49
64
1
48
60X (0.5)
SYMM
(8.8)
(1.36)
TYP
8X (1.31)
33
(
0.2) VIA
TYP
16
17
32
(1.36) TYP
8X (1.31)
(8.8)
LAND PATTERN EXAMPLE
SCALE:8X
0.07 MAX
ALL AROUND
0.07 MIN
ALL AROUND
METAL
SOLDER MASK
OPENING
SOLDER MASK
OPENING
METAL
NON SOLDER MASK
DEFINED
SOLDER MASK
DEFINED
(PREFERRED)
SOLDER MASK DETAILS
4214996/A 08/2013
NOTES: (continued)
4. This package is designed to be soldered to a thermal pad on the board. For more information, refer to QFN/SON PCB application note
in literature No. SLUA271 (www.ti.com/lit/slua271).
www.ti.com
EXAMPLE STENCIL DESIGN
NKD0064A
WQFN - 0.8 mm max height
WQFN
SYMM
(1.36) TYP
49
64X (0.6)
64X (0.25)
64
1
48
(1.36)
TYP
60X (0.5)
SYMM
(8.8)
METAL
TYP
16
33
17
32
25X (1.16)
(8.8)
SOLDERPASTE EXAMPLE
BASED ON 0.125mm THICK STENCIL
EXPOSED PAD
65% PRINTED SOLDER COVERAGE BY AREA
SCALE:10X
4214996/A 08/2013
NOTES: (continued)
5. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate
design recommendations.
www.ti.com
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Copyright © 2023, Texas Instruments Incorporated
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