LMK00338RTAR [TI]
LMK00338 8-Output Differential Clock Buffer/Level Translator; LMK00338 8路输出差分时钟缓冲器/电平转换器型号: | LMK00338RTAR |
厂家: | TEXAS INSTRUMENTS |
描述: | LMK00338 8-Output Differential Clock Buffer/Level Translator |
文件: | 总25页 (文件大小:1823K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LMK00338
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SNAS636 –DECEMBER 2013
LMK00338 8-Output Differential Clock Buffer/Level Translator
Check for Samples: LMK00338
1
FEATURES
APPLICATIONS
2
•
3:1 Input Multiplexer
•
Clock Distribution and Level Translation for
ADCs, DACs, Multi-Gigabit Ethernet, XAUI,
Fibre Channel, SATA/SAS, SONET/SDH, CPRI,
High-Frequency Backplanes
–
Two Universal Inputs Operate up to 400
MHz and Accept LVPECL, LVDS, CML,
SSTL, HSTL, HCSL, or Single-Ended Clocks
•
•
•
Switches, Routers, Line Cards, Timing Cards
Servers, Computing, PCI Express (PCIe 3.0)
Remote Radio Units and Baseband Units
–
One Crystal Input Accepts a 10 to 40 MHz
Crystal or Single-Ended Clock
•
Two Banks with 4 Differential Outputs Each
–
–
HCSL, or Hi-Z (Selectable Per Bank)
DESCRIPTION
Additive RMS Phase Jitter for PCIe Gen3 at
100MHz:
The LMK00338 is an 8-output PCIe Gen1/Gen2/Gen3
fanout buffer intended for high-frequency, low-jitter
clock/data distribution and level translation. The input
clock can be selected from two universal inputs or
one crystal input. The selected input clock is
distributed to two banks of 4 HCSL outputs and one
–
30 fs RMS (typical)
•
•
-72 dBc at 156.25 MHz
LVCMOS Output with Synchronous Enable
Input
LVCMOS output. The LVCMOS output has
a
•
•
•
Pin-Controlled Configuration
VCC Core Supply: 3.3 V ± 5%
synchronous enable input for runt-pulse-free
operation when enabled or disabled. The LMK00338
operates from a 3.3 V core supply and 3 independent
3.3 V/2.5 V output supplies.
3 Independent VCCO Output Supplies: 3.3 V/2.5
V ± 5%
The LMK00338 provides high performance,
versatility, and power efficiency, making it ideal for
replacing fixed-output buffer devices while increasing
timing margin in the system.
•
•
Industrial Temperature Range: -40°C to +85°C
40-lead WQFN (6 mm x 6 mm)
FUNCTIONAL BLOCK DIAGRAM
CLKoutA_EN
CLKoutB_EN
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2013, Texas Instruments Incorporated
LMK00338
SNAS636 –DECEMBER 2013
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Connection Diagram
40
39
38
37
36
35
34
33
32
31
CLKoutB0
CLKoutB0*
1
2
30
29
28
27
26
25
24
23
22
21
CLKoutA0
CLKoutA0*
3
V
CCOB
V
CCOA
CLKoutB1
CLKoutB1*
4
CLKoutA1
CLKoutA1*
5
Top Down View
6
V
CCOB
V
CCOA
CLKoutB2
CLKoutB2*
CLKoutB3
CLKoutB3*
7
CLKoutA2
CLKoutA2*
CLKoutA3
CLKoutA3*
8
DAP
9
10
11
12
13
14
15
16
17
18
19
20
Figure 1. 40-Pin Package
RTA0040A Package
Application Diagram
Mainboard
MAC
100MHz
Reference
Oscillator
PCI Express®
PHY
E.g.: XIO1100
Fan Out Buffer
E.g.: LMK00338
PCI Express®
fan-out switch
E.g.: XIO3130
Connector
FPGA with
PCI Express®
Core
PCI Express®
device
Data
Clock
Add-In Card
Figure 2. Example PCI Express Application
2
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PIN DESCRIPTIONS(1)
Pin #
DAP
1, 2
Pin Name(s)
DAP
Type
Description
GND
O
Die Attach Pad. Connect to the PCB ground plane for heat dissipation.
Differential clock output A0.
CLKoutA0, CLKoutA0*
Power supply for Bank A Output buffers. VCCOA can operate from 3.3 V or
2.5 V. The VCCOA pins are internally tied together. Bypass with a 0.1 uF
low-ESR capacitor placed very close to each Vcco pin.
3, 6
VCCOA
PWR
(2)
4, 5
7, 8
9, 10
11
CLKoutA1, CLKoutA1*
CLKoutA2, CLKoutA2*
CLKoutA3, CLKoutA3*
CLKoutA_EN
O
O
O
I
Differential clock output A1.
Differential clock output A2.
Differential clock output A3.
Bank A low active output buffer enable(3)
Power supply for Core and Input buffer blocks. The Vcc supply operates
from 3.3 V. Bypass with a 0.1 uF low-ESR capacitor placed very close to
each Vcc pin.
12, 32, 35,
39
Vcc
PWR
Input for crystal. Can also be driven by a XO, TCXO, or other external
single-ended clock.
13
14
OSCin
I
Output for crystal. Leave OSCout floating if OSCin is driven by a single-
ended clock.
OSCout
O
(3)
15, 18
16, 17
19
CLKin_SEL0, CLKin_SEL1
CLKin0, CLKin0*
CLKoutB_EN
I
Clock input selection pins
I
I
Universal clock input 0 (differential/single-ended)
Bank B low active output buffer enable(3)
Ground
20, 31, 40
21, 22
23, 24
GND
GND
O
CLKoutB3*, CLKoutB3
CLKoutB2*, CLKoutB2
Differential clock output B3.
O
Differential clock output B2.
Power supply for Bank B Output buffers. VCCOB can operate from 3.3 V or
2.5 V. The VCCOB pins are internally tied together. Bypass with a 0.1 uF
low-ESR capacitor placed very close to each Vcco pin.
25, 28
VCCOB
PWR
(2)
26, 27
29, 30
33, 34
36
CLKoutB1*, CLKoutB1
CLKoutB0*, CLKoutB0
CLKin1*, CLKin1
REFout
O
O
I
Differential clock output B1.
Differential clock output B0.
Universal clock input 1 (differential/single-ended)
LVCMOS reference output. Enable output by pulling REFout_EN pin high.
O
Power supply for REFout Output buffer. VCCOC can operate from 3.3 V or
2.5 V. Bypass with a 0.1 uF low-ESR capacitor placed very close to each
Vcco pin.
37
38
VCCOC
PWR
I
(2)
REFout enable input. Enable signal is internally synchronized to selected
REFout_EN
(3)
clock input.
(1) Any unused output pins should be left floating with minimum copper length (see note in Clock Outputs), or properly terminated if
connected to a transmission line, or disabled/Hi-Z if possible. See Clock Outputs for output configuration or Termination and Use of
Clock Drivers output interface and termination techniques.
(2) The output supply voltages/pins (VCCOA, VCCOB, and VCCOC) will be referred to generally as VCCO when no distinction is needed, or
when the output supply can be inferred by the output bank/type.
(3) CMOS control input with internal pull-down resistor.
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Functional Description
The LMK00338 is an 8-output PCIe Gen1/Gen2/Gen3 clock fanout buffer with low additive jitter that can operate
up to 400 MHz. It features a 3:1 input multiplexer with an optional crystal oscillator input, two banks of 4 HCSL
outputs, one LVCMOS output, and 3 independent output buffer supplies. The input selection and output buffer
modes are controlled via pin strapping. The device is offered in a 40-pin WQFN package and leverages much of
the high-speed, low-noise circuit design employed in the LMK04800 family of clock conditioners.
VCC and VCCO Power Supplies
The LMK00338 has a 3.3 V core power supply (VCC) and 3 independent 3.3 V/2.5 V output power supplies
(VCCOA, VCCOB, VCCOC). Output supply operation at 2.5 V enables lower power consumption and output-level
compatibility with 2.5 V receiver devices. The output levels for HCSL are relatively constant over the specified
Vcco range. Refer to Power Supply and Thermal Considerations for additional supply related considerations,
such as power dissipation, power supply bypassing, and power supply ripple rejection (PSRR).
NOTE
Care should be taken to ensure the Vcco voltages do not exceed the Vcc voltage to
prevent turning-on the internal ESD protection circuitry.
Clock Inputs
The input clock can be selected from CLKin0/CLKin0*, CLKin1/CLKin1*, or OSCin. Clock input selection is
controlled using the CLKin_SEL[1:0] inputs as shown in Table 1. Refer to Driving the Clock Inputs for clock input
requirements. When CLKin0 or CLKin1 is selected, the crystal circuit is powered down. When OSCin is selected,
the crystal oscillator circuit will start-up and its clock will be distributed to all outputs. Refer to Crystal Interface for
more information. Alternatively, OSCin may be be driven by a single-ended clock (up to 250 MHz) instead of a
crystal.
Table 1. Input Selection
CLKin_SEL1
CLKin_SEL0
Selected Input
CLKin0, CLKin0*
CLKin1, CLKin1*
OSCin
0
0
1
0
1
X
Table 2 shows the output logic state vs. input state when either CLKin0/CLKin0* or CLKin1/CLKin1* is selected.
When OSCin is selected, the output state will be an inverted copy of the OSCin input state.
Table 2. CLKin Input vs. Output States
State of
State of
Selected CLKin
Enabled Outputs
CLKinX and CLKinX*
inputs floating
Logic low
Logic low
CLKinX and CLKinX*
inputs shorted together
CLKin logic low
CLKin logic high
Logic low
Logic high
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Clock Outputs
The HCSL output buffer for Bank A and Bank B outputs can be separately disabled to Hi-Z using the
CLKoutA_EN and CLKoutB_EN inputs, respectively, as shown in Table 3. For applications where all differential
outputs are not needed, any unused output pin should be left floating with a minimum copper length (see note
below) to minimize capacitance and potential coupling and reduce power consumption. If an entire output bank
will not be used, it is recommended to disable/Hi-Z the bank to reduce power. Refer to Termination and Use of
Clock Drivers for more information on output interface and termination techniques.
NOTE
For best soldering practices, the minimum trace length for any unused output pin should
extend to include the pin solder mask. This way during reflow, the solder has the same
copper area as connected pins. This allows for good, uniform fillet solder joints helping to
keep the IC level during reflow.
Table 3. Differential Output Buffer Type Selection
CLKoutX Buffer Type
CLKoutX_EN
(Bank A or B)
0
1
HCSL
Disabled (Hi-Z)
Reference Output
The reference output (REFout) provides a LVCMOS copy of the selected input clock. The LVCMOS output high
level is referenced to the Vcco voltage. REFout can be enabled or disabled using the enable input pin,
REFout_EN, as shown in Table 4.
Table 4. Reference Output Enable
REFout_EN
REFout State
Disabled (Hi-Z)
Enabled
0
1
The REFout_EN input is internally synchronized with the selected input clock by the SYNC block. This
synchronizing function prevents glitches and runt pulses from occurring on the REFout clock when enabled or
disabled. REFout will be enabled within 3 cycles (tEN) of the input clock after REFout_EN is toggled high. REFout
will be disabled within 3 cycles (tDIS) of the input clock after REFout_EN is toggled low.
When REFout is disabled, the use of a resistive loading can be used to set the output to a predetermined level.
For example, if REFout is configured with a 1 kΩ load to ground, then the output will be pulled to low when
disabled.
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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.
ABSOLUTE MAXIMUM RATINGS(1)(2)(3)
Symbol
Ratings
VCC, VCCO
VIN
Units
-0.3 to 3.6
-0.3 to (VCC + 0.3)
-65 to +150
+260
Supply Voltages
Input Voltage
V
V
Storage Temperature Range
Lead Temperature (solder 4 s)
Junction Temperature
TSTG
°C
°C
°C
TL
TJ
+150
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but do not ensure specific performance limits. For ensured specifications and test
conditions, see ELECTRICAL CHARACTERISTICS. The ensured specifications apply only to the test conditions listed.
(2) This device is a high-performance integrated circuit with an ESD rating up to 2 kV Human Body Model, up to 150 V Machine Model, and
up to 750 V Charged Device Model and is ESD sensitive. Handling and assembly of this device should only be done at ESD-free
workstations.
(3) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
RECOMMENDED OPERATING CONDITIONS
Parameter
Ambient Temperature Range
Junction Temperature
Symbol
Min
Typ
Max
85
Units
°C
TA
-40
25
TJ
125
3.45
°C
Core Supply Voltage Range
VCC
3.15
3.3
V
3.3 – 5%
2.5 – 5%
3.3
2.5
3.3 + 5%
2.5 + 5%
Output Supply Voltage Range(1) (2)
VCCO
V
(1) The output supply voltages/pins (VCCOA, VCCOB, and VCCOC) will be referred to generally as VCCO when no distinction is needed, or
when the output supply can be inferred by the output bank/type.
(2) Vcco should be less than or equal to Vcc (Vcco ≤ Vcc).
PACKAGE THERMAL RESITANCE
Package
θJA
θJC (DAP)
(1)
40-Lead WQFN
31.4 °C/W
7.2 °C/W
(1) Specification assumes 9 thermal vias connect the die attach pad (DAP) to the embedded copper plane on the 4-layer JEDEC board.
These vias play a key role in improving the thermal performance of the package. It is recommended that the maximum number of vias
be used in the board layout.
6
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ELECTRICAL CHARACTERISTICS
Unless otherwise specified: Vcc = 3.3 V ± 5%, Vcco = 3.3 V ± 5%, 2.5 V ± 5%, -40 °C ≤ TA ≤ 85 °C, CLKin driven
differentially, input slew rate ≥ 3 V/ns. Typical values represent most likely parametric norms at Vcc = 3.3 V, Vcco = 3.3 V, TA
= 25 °C, and at the Recommended Operation Conditions at the time of product characterization and are not ensured.(1)(2)
SYMBOL
PARAMETER
CONDITIONS
Current Consumption(3)
CLKinX selected
MIN
TYP
MAX UNIT
8.5
10.5
mA
mA
mA
mA
Core Supply Current, All Outputs
Disabled
ICC_CORE
OSCin selected
10
31
13.5
38.5
5.5
ICC_HCSL
ICC_CMOS
3.5
Includes Output Bank Bias and Load Currents
for both banks, RT = 50 Ω on all outputs in
bank
Additive Output Supply Current,
HCSL Banks Enabled
ICCO_HCSL
ICCO_CMOS
68
84
mA
Vcco = 3.3 V ±5%
200 MHz, CL = 5 pF
9
7
10
8
mA
mA
Additive Output Supply Current,
LVCMOS Output Enabled
Vcco = 2.5V ± 5%
Power Supply Ripple Rejection (PSRR)
Ripple-Induced Phase Spur Level(4)
Differential HCSL Output
156.25 MHz
312.5 MHz
-72
-63
PSRRHCSL
dBc
CMOS Control Inputs (CLKin_SELn, CLKout_TYPEn, REFout_EN)
High-Level Input Voltage
VIH
VIL
IIH
1.6
Vcc
0.4
50
V
V
Low-Level Input Voltage
High-Level Input Current
Low-Level Input Current
GND
VIH = Vcc, Internal pull-down resistor
VIL = 0 V, Internal pull-down resistor
μA
μA
IIL
-5
0.1
Clock Inputs (CLKin0/CLKin0*, CLKin1/CLKin1*)
Functional up to 400 MHz
Output frequency range and timing specified
per output type (refer to HCSL, LVCMOS
output specifications)
fCLKin
Input Frequency Range(5)
DC
400
Vcc
1.3
MHz
VIHD
VILD
VID
Differential Input High Voltage
Differential Input Low Voltage
Differential Input Voltage Swing(6)
V
V
V
CLKin driven differentially
GND
0.15
Vcc -
1.2
VID = 150 mV
VID = 350 mV
VID = 800 mV
0.25
0.25
0.25
Differential Input CMD Common
Mode Voltage
Vcc -
1.1
VCMD
V
Vcc -
0.9
VIH
VIL
Single-Ended Input IH High Voltage
Single-Ended Input IL Low Voltage
Single-Ended Input Voltage Swing(7)
VCC
V
V
GND
0.3
CLKinX driven single-ended (AC or DC
coupled), CLKinX* AC coupled to GND or
externally biased within VCM range
VI_SE
2
Vpp
Single-Ended Input CM Common
Mode Voltage
VCC -
1.2
VCM
0.25
V
(1) The output supply voltages/pins (VCCOA, VCCOB, and VCCOC) will be referred to generally as VCCO when no distinction is needed, or
when the output supply can be inferred by the output bank/type.
(2) The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as
otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and
are not ensured.
(3) See Power Supply and Thermal Considerations for more information on current consumption and power dissipation calculations.
(4) Power supply ripple rejection, or PSRR, is defined as the single-sideband phase spur level (in dBc) modulated onto the clock output
when a single-tone sinusoidal signal (ripple) is injected onto the Vcco supply. Assuming no amplitude modulation effects and small index
modulation, the peak-to-peak deterministic jitter (DJ) can be calculated using the measured single-sideband phase spur level (PSRR) as
follows: DJ (ps pk-pk) = [ (2 * 10(PSRR / 20)) / (π * fCLK) ] * 1E12
(5) Specification is ensured by characterization and is not tested in production.
(6) See Differential Voltage Measurement Terminology for definition of VID and VOD voltages.
(7) Parameter is specified by design, not tested in production.
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ELECTRICAL CHARACTERISTICS (continued)
Unless otherwise specified: Vcc = 3.3 V ± 5%, Vcco = 3.3 V ± 5%, 2.5 V ± 5%, -40 °C ≤ TA ≤ 85 °C, CLKin driven
differentially, input slew rate ≥ 3 V/ns. Typical values represent most likely parametric norms at Vcc = 3.3 V, Vcco = 3.3 V, TA
= 25 °C, and at the Recommended Operation Conditions at the time of product characterization and are not ensured.(1)(2)
SYMBOL
PARAMETER
CONDITIONS
fCLKin0 = 100 MHz
MIN
TYP
-84
MAX UNIT
fCLKin0 = 200 MHz
fCLKin0 = 500 MHz
fCLKin0 = 1000 MHz
-82
-71
-65
fOFFSET > 50 kHz,
PCLKinX = 0 dBm
ISOMUX
Mux Isolation, CLKin0 to CLKin1
dBc
Crystal Interface (OSCin, OSCout)
FCLK
FXTAL
CIN
External Clock Frequency Range(8)
OSCin driven single-ended, OSCout floating
250
40
MHz
MHz
pF
Fundamental mode crystal ESR ≤ 200 Ω (10
to 30 MHz) ESR ≤ 125 Ω (30 to 40 MHz)(9)
Crystal Frequency Range
10
OSCin Input Capacitance
1
HCSL Outputs (CLKoutAn/CLKoutAn*, CLKoutBn/CLKoutBn*)
Output Frequency Range(8)
RL = 50 Ω to GND, CL ≤ 5 pF
fCLKout
DC
400
MHz
ps
PCIe Gen 3, PLL BW
Additive RMS Phase Jitter for PCIe
3.0(8)
CLKin: 100 MHz,
JitterADD_PCle
= 2–5 MHz, CDR = 10
MHz
0.03
0.15
Slew rate ≥ 0.6 V/ns
CLKin: 100 MHz,
Slew rate ≥ 3 V/ns
77
Additive RMS Jitter Integration
Vcco = 3.3 V,
RT = 50 Ω to GND
JitterADD
fs
Bandwidth 1 MHz to 20 MHz(10)(11)
CLKin: 156.25 MHz,
Slew rate ≥ 2.7 V/ns
86
CLKin: 100 MHz,
Slew rate ≥ 3 V/ns
-161.3
-156.3
Vcco = 3.3 V,
RT = 50 Ω to GND
Noise Floor
Noise Floor fOFFSET ≥ 10 MHz(10)(11)
dBc/Hz
CLKin: 156.25 MHz,
Slew rate ≥ 2.7 V/ns
DUTY
VOH
Duty Cycle(8)
Output High Voltage
50% input clock duty cycle
45
55
%
520
810
0.5
920
mV
TA = 25 °C, DC Measurement, RT = 50 Ω to
GND
-150
160
150
460
140
mV
mV
mV
VOL
Output Low Voltage
Absolute Crossing Voltage(8)(12)
350
VCROSS
ΔVCROSS
RL = 50 Ω to GND, CL ≤ 5 pF
Total Variation of VCROSS
Output Rise Time 20% to
80%(12)(13)
Output Fall Time 80% to 20%(12)(13)
250 MHz, Uniform transmission line up to 10
in. with 50-Ω characteristic impedance, RL =
50 Ω to GND, CL ≤ 5 pF
tR
tF
300
300
500
500
ps
ps
(8) Specification is ensured by characterization and is not tested in production.
(9) The ESR requirements stated must be met to ensure that the oscillator circuitry has no startup issues. However, lower ESR values for
the crystal may be necessary to stay below the maximum power dissipation (drive level) specification of the crystal. Refer to Crystal
Interface for crystal drive level considerations.
(10) The noise floor of the output buffer is measured as the far-out phase noise of the buffer. Typically this offset is ≥ 10 MHz, but for lower
frequencies this measurement offset can be as low as 5 MHz due to measurement equipment limitations.
(11) Phase noise floor will degrade as the clock input slew rate is reduced. Compared to a single-ended clock, a differential clock input
(LVPECL, LVDS) will be less susceptible to degradation in noise floor at lower slew rates due to its common mode noise rejection.
However, it is recommended to use the highest possible input slew rate for differential clocks to achieve optimal noise floor performance
at the device outputs.
(12) AC timing parameters for HCSL or CMOS are dependent on output capacitive loading.
(13) Parameter is specified by design, not tested in production.
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ELECTRICAL CHARACTERISTICS (continued)
Unless otherwise specified: Vcc = 3.3 V ± 5%, Vcco = 3.3 V ± 5%, 2.5 V ± 5%, -40 °C ≤ TA ≤ 85 °C, CLKin driven
differentially, input slew rate ≥ 3 V/ns. Typical values represent most likely parametric norms at Vcc = 3.3 V, Vcco = 3.3 V, TA
= 25 °C, and at the Recommended Operation Conditions at the time of product characterization and are not ensured.(1)(2)
SYMBOL
PARAMETER
CONDITIONS
LVCMOS Output (REFout)
CL ≤ 5 pF
MIN
TYP
MAX UNIT
fCLKout
Output Frequency Range(14)
DC
250
MHz
fs
Additive RMS Jitter Integration
Bandwidth 1 MHz to 20 MHz(15)
Vcco = 3.3 V, CL ≤ 5 100 MHz, Input Slew
JitterADD
95
pF
Vcco = 3.3 V, CL ≤ 5 100 MHz, Input Slew
pF rate ≥ 3 V/ns
rate ≥ 3 V/ns
Noise Floor
DUTY
VOH
Noise Floor fOFFSET ≥ 10 MHz(16)(17)
Duty Cycle(14)
-159.3
dBc/Hz
50% input clock duty cycle
45
55
%
V
Vcco -
0.1
Output High Voltage
1 mA load
VOL
Output Low Voltage
0.1
V
Vcco = 3.3 V
28
20
28
mA
Vcco = 2.5 V
Vcco = 3.3 V
IOH
Output High Current (Source)
Output Low Current (Sink)
Vo = Vcco / 2
mA
ps
Vcco = 2.5 V
20
IOL
tR
Output Rise Time 20% to
80%(18)(19)
Output Fall Time 80% to 20%(18)(19)
Output Enable Time(20)
250 MHz, Uniform transmission line up to 10
in. with 50-Ω characteristic impedance, RL =
50 Ω to GND, CL ≤ 5 pF
225
225
400
tF
400
3
ps
tEN
tDIS
cycles
cycles
CL ≤ 5 pF
Output Disable Time(20)
3
Propagation Delay and Output Skew
Propagation Delay CLKin-to-
HCSL(18)(19)
tPD_HCSL
tPD_CMOS
RT = 50 Ω to GND, CL ≤ 5 pF
295
590
885
ps
ps
Vcco = 3.3 V
Vcco = 2.5 V
900
1475
1550
30
2300
2700
50
Propagation Delay CLKin-to-
LVCMOS(18)(19)
CL ≤ 5 pF
1000
tSK(O)
Output Skew(14)(18)(21)
ps
ps
Skew specified between any two CLKouts.
Load conditions are the same as propagation
delay specifications.
Part-to-Part Output Skew
tSK(PP)
80
120
LVPECL/LVDS/HCSL(18)(19)(21)
(14) Specification is ensured by characterization and is not tested in production.
2
(15) For the 100 MHz and 156.25 MHz clock input conditions, Additive RMS Jitter (JADD) is calculated using Method #1: JADD = SQRT(JOUT
- JSOURCE2), where JOUT is the total RMS jitter measured at the output driver and JSOURCE is the RMS jitter of the clock source applied to
CLKin. For the 625 MHz clock input condition, Additive RMS Jitter is approximated using Method #2: JADD = SQRT(2*10dBc/10) /
(2*π*fCLK), where dBc is the phase noise power of the Output Noise Floor integrated from 1 to 20 MHz bandwidth. The phase noise
power can be calculated as: dBc = Noise Floor + 10*log10(20 MHz - 1 MHz). The additive RMS jitter was approximated for 625 MHz
using Method #2 because the RMS jitter of the clock source was not sufficiently low enough to allow practical use of Method #1. Refer
to the “Noise Floor vs. CLKin Slew Rate” and “RMS Jitter vs. CLKin Slew Rate” plots in TYPICAL CHARACTERISTICS.
(16) The noise floor of the output buffer is measured as the far-out phase noise of the buffer. Typically this offset is ≥ 10 MHz, but for lower
frequencies this measurement offset can be as low as 5 MHz due to measurement equipment limitations.
(17) Phase noise floor will degrade as the clock input slew rate is reduced. Compared to a single-ended clock, a differential clock input
(LVPECL, LVDS) will be less susceptible to degradation in noise floor at lower slew rates due to its common mode noise rejection.
However, it is recommended to use the highest possible input slew rate for differential clocks to achieve optimal noise floor performance
at the device outputs.
(18) AC timing parameters for HCSL or CMOS are dependent on output capacitive loading.
(19) Parameter is specified by design, not tested in production.
(20) Output Enable Time is the number of input clock cycles it takes for the output to be enabled after REFout_EN is pulled high. Similarly,
Output Disable Time is the number of input clock cycles it takes for the output to be disabled after REFout_EN is pulled low. The
REFout_EN signal should have an edge transition much faster than that of the input clock period for accurate measurement.
(21) Output skew is the propagation delay difference between any two outputs with identical output buffer type and equal loading while
operating at the same supply voltage and temperature conditions.
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MEASUREMENT DEFINITIONS
Differential Voltage Measurement Terminology
The differential voltage of a differential signal can be described by two different definitions causing confusion
when reading datasheets or communicating with other engineers. This section will address the measurement and
description of a differential signal so that the reader will be able to understand and discern between the two
different definitions when used.
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. Nowhere in the IC does this signal exist 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 3 illustrates the two different definitions side-by-side for inputs and Figure 4 illustrates the two different
definitions side-by-side for outputs. The VID (or VOD) definition show the DC levels, VIH and VOL (or VOH and VOL),
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
IH
V
V
SS
V
ID
CM
V
IL
Inverting Clock
V
= | V ± V
|
V
SS
= 2·V
ID
ID
IH IL
GND
Figure 3. Two Different Definitions for Differential Input Signals
V
Definition
V
Definition for Output
SS
OD
Non-Inverting Clock
V
V
OH
V
V
OS
SS
OD
V
OL
Inverting Clock
= | V - V
V
OD
|
V
SS
= 2·V
OD
OH OL
GND
Figure 4. Two Different Definitions for Differential Output Signals
Refer to Application Note AN-912 (literature number SNLA036), Common Data Transmission Parameters and
their Definitions, for more information.
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TYPICAL CHARACTERISTICS
Unless otherwise specified: Vcc = 3.3 V, Vcco = 3.3 V, TA = 25 °C, CLKin driven differentially, input slew rate ≥ 3 V/ns.
HCSL Output Swing @ 250 MHz
LVCMOS Output Swing @ 250 MHz
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
1.00
0.75
0.50
0.25
0.00
-0.25
-0.50
-0.75
-1.00
Vcco=3.3 V, AC coupled, 50ꢀꢀload
Vcco=2.5 V, AC coupled, 50ꢀꢀload
0
1
2
3
4
5
0
1
2
3
4
5
6
TIME (ns)
TIME (ns)
Figure 5.
Figure 6.
Noise Floor vs. CLKin Slew Rate @ 100 MHz
-140
Noise Floor vs. CLKin Slew Rate @ 156.25 MHz
-135
Fclk=156.25 MHz
HCSL
Foffset=20 MHz
CLKin Source
Fclk=100 MHz
HCSL
LVCMOS
CLKin Source
-140
-145
-150
-155
-160
-165
-170
Foffset=20 MHz
-145
-150
-155
-160
-165
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0.5
1.0
1.5
2.0
2.5
3.0
3.5
DIFFERENTIAL INPUT SLEW RATE (V/ns)
DIFFERENTIAL INPUT SLEW RATE (V/ns)
Figure 7.
Figure 8.
RMS Jitter vs. CLKin Slew Rate @ 100 MHz
400
RMS Jitter vs. CLKin Slew Rate @ 156.25 MHz
500
Fclk=100 MHz
Int. BW=1-20 MHz
450
400
350
300
250
200
150
100
50
Fclk=156.25 MHz
Int. BW=1-20 MHz
350
HCSL
LVCMOS
CLKin Source
HCSL
CLKin Source
300
250
200
150
100
50
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0.5
1.0
1.5
2.0
2.5
3.0
3.5
DIFFERENTIAL INPUT SLEW RATE (V/ns)
DIFFERENTIAL INPUT SLEW RATE (V/ns)
Figure 9.
Figure 10.
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TYPICAL CHARACTERISTICS (continued)
Unless otherwise specified: Vcc = 3.3 V, Vcco = 3.3 V, TA = 25 °C, CLKin driven differentially, input slew rate ≥ 3 V/ns.
PSRR vs. Ripple Frequency @ 156.25 MHz
-50
PSRR vs. Ripple Frequency @ 312.5 MHz
-50
Fclk=156.25 MHz
Vcco Ripple=100 mVpp
Fclk=312.5 MHz
Vcco Ripple=100 mVpp
-55
-60
-65
-70
-75
-80
-85
-90
-55
-60
-65
-70
-75
-80
-85
-90
HCSL
HCSL
.1
1
10
.1
1
10
RIPPLE FREQUENCY (MHz)
RIPPLE FREQUENCY (MHz)
Figure 11.
Figure 12.
Propagation Delay vs. Temperature
1950
Crystal Power Dissipation vs. RLIM
850
200
175
150
125
100
75
20 MHz Crystal
40 MHz Crystal
HCSL (0.35 ps/°C)
1850
750
650
550
450
350
250
LVCMOS (2.2 ps/°C)
Right Y-axis plot
1750
1650
1550
1450
1350
50
25
0
-50 -25
0
25
50
75 100
0
500 1k 1.5k 2k 2.5k 3k 3.5k 4k
(ꢁ)
TEMPERATURE (°C)
R
LIM
Figure 13.
Figure 14.
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TYPICAL CHARACTERISTICS (continued)
Unless otherwise specified: Vcc = 3.3 V, Vcco = 3.3 V, TA = 25 °C, CLKin driven differentially, input slew rate ≥ 3 V/ns.
LVPECL Phase Noise @ 100 MHz
Figure 15.
HCSL Phase Noise @ 100 MHz
Figure 16.
(1) The typical RMS jitter values in the plots show the total output RMS jitter (JOUT) for each output buffer type and the
source clock RMS jitter (JSOURCE). From these values, the Additive RMS Jitter can be calculated as: JADD
=
SQRT(JOUT2 - JSOURCE2).
(2) 20 MHz crystal characteristics: Abracon ABL series, AT cut, CL = 18 pF , C0 = 4.4 pF measured (7 pF max), ESR =
8.5 Ω measured (40 Ω max), and Drive Level = 1 mW max (100 µW typical).
(3) 40 MHz crystal characteristics: Abracon ABLS2 series, AT cut, CL = 18 pF , C0 = 5 pF measured (7 pF max), ESR =
5 Ω measured (40 Ω max), and Drive Level = 1 mW max (100 µW typical).
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APPLICATION INFORMATION
Driving the Clock Inputs
The LMK00338 has two universal inputs (CLKin0/CLKin0* and CLKin1/CLKin1*) that can accept AC- or DC-
coupled 3.3V/2.5V LVPECL, LVDS, CML, SSTL, and other differential and single-ended signals that meet the
input requirements specified in the ELECTRICAL CHARACTERISTICS. The device can accept a wide range of
signals due to its wide input common mode voltage range (VCM ) and input voltage swing (VID) / dynamic range.
For 50% duty cycle and DC-balanced signals, AC coupling may also be employed to shift the input signal to
within the VCM range. Refer to Termination and Use of Clock Drivers for signal interfacing and termination
techniques.
To achieve the best possible phase noise and jitter performance, it is mandatory for the input to have high slew
rate of 3 V/ns (differential) or higher. Driving the input with a lower slew rate will degrade the noise floor and jitter.
For this reason, a differential signal input is recommended over single-ended because it typically provides higher
slew rate and common-mode-rejection. Refer to the Noise Floor vs. CLKin Slew Rate and RMS Jitter vs. CLKin
Slew Rate plots in TYPICAL CHARACTERISTICS.
While it is recommended to drive the CLKin/CLKin* pair with a differential signal input, it is possible to drive it
with a single-ended clock provided it conforms to the Single-Ended Input specifications for CLKin pins listed in
the ELECTRICAL CHARACTERISTICS. For large single-ended input signals, such as 3.3V or 2.5V LVCMOS, a
50 Ω load resistor should be placed near the input for signal attenuation to prevent input overdrive as well as for
line termination to minimize reflections. Again, the single-ended input slew rate should be as high as possible to
minimize performance degradation. The CLKin input has an internal bias voltage of about 1.4 V, so the input can
be AC coupled as shown in Figure 17. The output impedance of the LVCMOS driver plus Rs should be close to
50 Ω to match the characteristic impedance of the transmission line and load termination.
0.1 PF
0.1 PF
R
S
50:ꢀTrace
CMOS
Driver
LMK
Input
0.1 PF
Figure 17. Single-Ended LVCMOS Input, AC Coupling
A single-ended clock may also be DC coupled to CLKinX as shown in Figure 18. A 50-Ω load resistor should be
placed near the CLKinX input for signal attenuation and line termination. Because half of the single-ended swing
of the driver (VO,PP / 2) drives CLKinX, CLKinX* should be externally biased to the midpoint voltage of the
attenuated input swing ((VO,PP / 2) × 0.5). The external bias voltage should be within the specified input common
voltage (VCM) range. This can be achieved using external biasing resistors in the kΩ range (RB1 and RB2) or
another low-noise voltage reference. This will ensure the input swing crosses the threshold voltage at a point
where the input slew rate is the highest.
VO,PP
Rs
VO,PP/2
V
CC
50:ꢀTrace
CMOS
Driver
50:
LMK
Input
VBB ~ (VO,PP/2) x 0.5
R
B1
V
CC
R
B2
0.1 PF
Figure 18. Single-Ended LVCMOS Input, DC Coupling
with Common Mode Biasing
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If the crystal oscillator circuit is not used, it is possible to drive the OSCin input with an single-ended external
clock as shown in Figure 19. The input clock should be AC coupled to the OSCin pin, which has an internally-
generated input bias voltage, and the OSCout pin should be left floating. While OSCin provides an alternative
input to multiplex an external clock, it is recommended to use either differential input (CLKinX) since it offers
higher operating frequency, better common mode and power supply noise rejection, and greater performance
over supply voltage and temperature variations.
0.1 PF
0.1 PF
R
S
50:ꢀTrace
OSCin
CMOS
Driver
OSCout
Figure 19. Driving OSCin with a Single-Ended Input
Crystal Interface
The LMK00338 has an integrated crystal oscillator circuit that supports a fundamental mode, AT-cut crystal. The
crystal interface is shown in Figure 20.
C
1
OSCin
XTAL
R
LIM
OSCout
C
2
Figure 20. Crystal Interface
The load capacitance (CL) is specific to the crystal, but usually on the order of 18 - 20 pF. While CL is specified
for the crystal, the OSCin input capacitance (CIN = 1 pF typical) of the device and PCB stray capacitance (CSTRAY
~ 1~3 pF) can affect the discrete load capacitor values, C1 and C2.
For the parallel resonant circuit, the discrete capacitor values can be calculated as follows:
CL = (C1 * C2) / (C1 + C2) + CIN + CSTRAY
(1)
(2)
(3)
Typically, C1 = C2 for optimum symmetry, so Equation 1 can be rewritten in terms of C1 only:
CL = C12 / (2 * C1) + CIN + CSTRAY
Finally, solve for C1:
C1 = (CL - CIN - CSTRAY)*2
ELECTRICAL CHARACTERISTICS provides crystal interface specifications with conditions that ensure start-up
of the crystal, but it does not specify crystal power dissipation. The designer will need to ensure the crystal power
dissipation does not exceed the maximum drive level specified by the crystal manufacturer. Overdriving the
crystal can cause premature aging, frequency shift, and eventual failure. Drive level should be held at a sufficient
level necessary to start-up and maintain steady-state operation.
The power dissipated in the crystal, PXTAL, can be computed by:
PXTAL = IRMS2 * RESR*(1 + C0/CL)2
where
•
•
•
•
IRMS is the RMS current through the crystal.
RESR is the max. equivalent series resistance specified for the crystal
CL is the load capacitance specified for the crystal
C0 is the min. shunt capacitance specified for the crystal
(4)
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IRMS can be measured using a current probe (for example, Tektronix CT-6 or equivalent) placed on the leg of the
crystal connected to OSCout with the oscillation circuit active.
As shown in Figure 20, an external resistor, RLIM, can be used to limit the crystal drive level, if necessary. If the
power dissipated in the selected crystal is higher than the drive level specified for the crystal with RLIM shorted,
then a larger resistor value is mandatory to avoid overdriving the crystal. However, if the power dissipated in the
crystal is less than the drive level with RLIM shorted, then a zero value for RLIM can be used. As a starting point, a
suggested value for RLIM is 1.5 kΩ.
Termination and Use of Clock Drivers
When terminating clock drivers keep in mind these guidelines for optimum phase noise and jitter performance:
•
•
Transmission line theory should be followed for good impedance matching to prevent reflections.
Clock drivers should be presented with the proper loads.
–
HCSL drivers are switched current outputs and require a DC path to ground via 50 Ω termination.
•
Receivers should be presented with a signal biased to their specified DC bias level (common mode voltage)
for proper operation. Some receivers have self-biasing inputs that automatically bias to the proper voltage
level; in this case, the signal should normally be AC coupled.
Termination for DC Coupled Differential Operation
For DC coupled operation of an HCSL driver, terminate with 50 Ω to ground near the driver output as shown in
Figure 21. Series resistors, Rs, may be used to limit overshoot due to the fast transient current. Because HCSL
drivers require a DC path to ground, AC coupling is not allowed between the output drivers and the 50 Ω
termination resistors.
Rs
CLKoutX
HCSL
Driver
HCSL
Receiver
50:ꢀTraces
Rs
CLKoutX*
Figure 21. HCSL Operation, DC Coupling
Termination for AC Coupled Differential Operation
AC coupling allows for shifting the DC bias level (common mode voltage) when driving different receiver
standards. Since AC coupling prevents the driver from providing a DC bias voltage at the receiver, it is important
to ensure the receiver is biased to its ideal DC level.
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Power Supply and Thermal Considerations
Current Consumption and Power Dissipation Calculations
The current consumption values specified in ELECTRICAL CHARACTERISTICS can be used to calculate the
total power dissipation and IC power dissipation for any device configuration. The total VCC core supply current
(ICC_TOTAL) can be calculated using Equation 5:
ICC_TOTAL = ICC_CORE + ICC_BANK_A + ICC_BANK_B + ICC_CMOS
where
•
•
•
•
ICC_CORE is the current for core logic and input blocks and depends on selected input (CLKinX or OSCin).
ICC_BANK_A is the current for Bank A.
ICC_BANK_B is the current for Bank B.
ICC_CMOS is the current for the LVCMOS output (or 0 mA if REFout is disabled).
(5)
Since the output supplies (VCCOA, VCCOB, VCCOC) can be powered from 3 independent voltages, the respective
output supply currents (ICCO_BANK_A, ICCO_BANK_B, and ICCO_CMOS) should be calculated separately. ICCO_BANK for
either Bank A or B can be directly taken from the corresponding output supply current spec (ICCO_HCSL) provided
the output loading matches the specified conditions. Otherwise, ICCO_BANK should be calculated as follows:
ICCO_BANK = IBANK_BIAS + (N * IOUT_LOAD
)
where
•
•
•
IBANK_BIAS is the output bank bias current (fixed value).
IOUT_LOAD is the DC load current per loaded output pair.
N is the number of loaded output pairs per bank (N = 0 to 4).
(6)
Table 5 shows the typical IBANK_BIAS values and IOUT_LOAD expressions for HCSL.
Table 5. Typical Output Bank Bias and Load Currents
Current Parameter
IBANK_BIAS
HCSL
4.8 mA
VOH/RT
IOUT_LOAD
Once the current consumption is calculated for each supply, the total power dissipation (PTOTAL) can be
calculated as:
PTOTAL = (VCC*ICC_TOTAL) + (VCCOA*ICCO_BANK_A) + (VCCOB*ICCO_BANK_B) + (VCCOC*ICCO_CMOS
)
(7)
If the device configuration is configured with HCSL outputs, then it is also necessary to calculate the power
dissipated in any termination resistors (PRT_HCSL). The external power dissipation values can be calculated as
follows:
PRT_HCSL (per HCSL pair) = VOH2 / RT
(8)
Finally, the IC power dissipation (PDEVICE) can be computed by subtracting the external power dissipation values
from PTOTAL as follows:
PDEVICE = PTOTAL - N*PRT_HCSL
where
•
N2 is the number of HCSL output pairs with termination resistors to GND.
(9)
Power Dissipation Example: Worst-Case Dissipation
This example shows how to calculate IC power dissipation for a configuration to estimate worst-case power
dissipation. In this case, the maximum supply voltage and supply current values specified in ELECTRICAL
CHARACTERISTICS are used.
•
•
•
•
•
VCC = VCCO = 3.465 V. Max ICC and ICCO values.
CLKin0/CLKin0* input is selected.
Banks A and B are enabled: all outputs terminated with 50 Ω to GND.
REFout is enabled with 5 pF load.
TA = 85 °C
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Using the power calculations from the previous section and maximum supply current specifications, we can
compute PTOTAL and PDEVICE
.
•
•
•
•
•
From Equation 5: ICC_TOTAL = 10.5 mA + 38.5 mA + 38.5 mA + 5.5 mA = 93 mA
From ICCO_HCSL max spec: ICCO_BANK_A = ICCO_BANK_B = 84 mA
From Equation 7: PTOTAL = 3.465 V * (93 mA + 84 mA + 84 mA + 10 mA) = 939 mW
From Equation 8: PRT_HCSL = (0.92V)2/50Ω = 16.9 mW (per output pair)
From Equation 9: PDEVICE = 939 mW - (8 * 16.9 mW) = 803.8 mW
In this worst-case example, the IC device will dissipate about 803.8 mW or 85.6 of the total power (939 mW),
while the remaining 14.4% will be dissipated in the termination resistors (135.2 mW for 8 pairs). Based on θJA of
31.4 °C/W, the estimated die junction temperature would be about 25.2 °C above ambient, or 110.2 °C when TA
= 85 °C.
Power Supply Bypassing
The Vcc and Vcco power supplies should have a high-frequency bypass capacitor, such as 0.1 uF or 0.01 uF,
placed very close to each supply pin. 1 uF to 10 uF decoupling capacitors should also be placed nearby the
device between the supply and ground planes. All bypass and decoupling capacitors should have short
connections to the supply and ground plane through a short trace or via to minimize series inductance.
Power Supply Ripple Rejection
In practical system applications, power supply noise (ripple) can be generated from switching power supplies,
digital ASICs or FPGAs, and so on. While power supply bypassing will help filter out some of this noise, it is
important to understand the effect of power supply ripple on the device performance. When a single-tone
sinusoidal signal is applied to the power supply of a clock distribution device, such as LMK00338, it can produce
narrow-band phase modulation as well as amplitude modulation on the clock output (carrier). In the single-side
band phase noise spectrum, the ripple-induced phase modulation appears as a phase spur level relative to the
carrier (measured in dBc).
For the LMK00338, power supply ripple rejection, or PSRR, was measured as the single-sideband phase spur
level (in dBc) modulated onto the clock output when a ripple signal was injected onto the Vcco supply. The
PSRR test setup is shown in Figure 22.
Ripple
Source
Power
Supplies
Bias-Tee
Vcco
Vcc
OUT+
IN+
IN-
Clock
Source
Limiting
Amp
IC
OUT-
DUT Board
OUT
Phase Noise
Analyzer
Scope
Measure 100 mV
Measure single
PP
sideband phase spur
power in dBc
ripple on Vcco at IC
Figure 22. PSRR Test Setup
A signal generator was used to inject a sinusoidal signal onto the Vcco supply of the DUT board, and the peak-
to-peak ripple amplitude was measured at the Vcco pins of the device. A limiting amplifier was used to remove
amplitude modulation on the differential output clock and convert it to a single-ended signal for the phase noise
analyzer. The phase spur level measurements were taken for clock frequencies of 156.25 MHz and 312.5 MHz
under the following power supply ripple conditions:
•
•
Ripple amplitude: 100 mVpp on Vcco = 2.5 V
Ripple frequencies: 100 kHz, 1 MHz, and 10 MHz
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Assuming no amplitude modulation effects and small index modulation, the peak-to-peak deterministic jitter (DJ)
can be calculated using the measured single-sideband phase spur level (PSRR) as follows:
DJ (ps pk-pk) = [(2*10(PSRR / 20)) / (π*fCLK)] * 1012
(10)
The PSRR vs. Ripple Frequency plots in TYPICAL CHARACTERISTICS show the ripple-induced phase spur
levels at 156.25 MHz and 312.5 MHz. The LMK00338 exhibits very good and well-behaved PSRR characteristics
across the ripple frequency range. The phase spur levels for HCSL are below -72 dBc at 156.25 MHz and below
-63 dBc at 312.5 MHz. Using Equation 10, these phase spur levels translate to Deterministic Jitter values of 1.02
ps pk-pk at 156.25 MHz and 1.44 ps pk-pk at 312.5 MHz. Testing has shown that the PSRR performance of the
device improves for Vcco = 3.3 V under the same ripple amplitude and frequency conditions.
Thermal Management
Power dissipation in the LMK00338 device 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 dissipation times θJA 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 the 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.
A recommended land and via pattern is shown in Figure 23. More information on soldering WQFN packages can
be obtained at: http://www.ti.com/packaging.
4.6 mm, min
0.2 mm,
typ
1.2 mm,
typ
Figure 23. Recommended Land and Via Pattern
To minimize junction temperature it is recommended that a simple heat sink be built into the PCB (if the ground
plane layer is not exposed). This is done by including a copper area of about 2 square inches on the opposite
side of the PCB from the device. This copper area may be plated or solder coated to prevent corrosion but
should not have conformal coating (if possible), which could provide thermal insulation. The vias shown in
Figure 23 should connect these top and bottom copper layers and to the ground layer. These vias act as “heat
pipes” to carry the thermal energy away from the device side of the board to where it can be more effectively
dissipated.
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PACKAGE OPTION ADDENDUM
www.ti.com
22-Dec-2013
PACKAGING INFORMATION
Orderable Device
LMK00338RTAR
LMK00338RTAT
Status Package Type Package Pins Package
Eco Plan
Lead/Ball Finish
MSL Peak Temp
Op Temp (°C)
-40 to 85
Device Marking
Samples
Drawing
Qty
(1)
(2)
(6)
(3)
(4/5)
ACTIVE
WQFN
WQFN
RTA
40
40
1000
Green (RoHS
& no Sb/Br)
SN
Level-3-260C-168 HR
K00338
K00338
ACTIVE
RTA
250
Green (RoHS
& no Sb/Br)
SN
Level-3-260C-168 HR
-40 to 85
(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) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(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.
(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish 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.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
22-Dec-2013
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.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
23-Dec-2013
TAPE AND REEL INFORMATION
*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)
LMK00338RTAR
LMK00338RTAT
WQFN
WQFN
RTA
RTA
40
40
1000
250
330.0
178.0
16.4
16.4
6.3
6.3
6.3
6.3
1.5
1.5
12.0
12.0
16.0
16.0
Q1
Q1
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
23-Dec-2013
*All dimensions are nominal
Device
Package Type Package Drawing Pins
SPQ
Length (mm) Width (mm) Height (mm)
LMK00338RTAR
LMK00338RTAT
WQFN
WQFN
RTA
RTA
40
40
1000
250
367.0
213.0
367.0
191.0
38.0
55.0
Pack Materials-Page 2
MECHANICAL DATA
RTA0040A
SQA40A (Rev B)
www.ti.com
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