AD9644CCPZRL7-80 [ADI]
14-Bit, 80 MSPS/155 MSPS, 1.8V Dual, Serial Output A/D Converter;型号: | AD9644CCPZRL7-80 |
厂家: | ADI |
描述: | 14-Bit, 80 MSPS/155 MSPS, 1.8V Dual, Serial Output A/D Converter 转换器 |
文件: | 总44页 (文件大小:1886K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
14-Bit, 80 MSPS/155 MSPS, 1.8 V Dual
Serial Output Analog-to-Digital Converter (ADC)
Data Sheet
AD9644
FEATURES
FUNCTIONAL BLOCK DIAGRAM
AVDD
AGND
DRVDD
DRGND
JESD204A coded serial digital outputs
SNR = 73.7 dBFS at 70 MHz and 80 MSPS
SNR = 71.7 dBFS at 70 MHz and 155 MSPS
SFDR = 92 dBc at 70 MHz and 80 MSPS
SFDR = 92 dBc at 70 MHz and 155 MSPS
Low power: 423 mW at 80 MSPS, 567 mW at 155 MSPS
1.8 V supply operation
AD9644
DOUT+A
DOUT–A
VIN+A
14
PIPELINE
14-BIT ADC
DSYNC+A
DSYNC–A
VIN–A
VCMA
DOUT+B
DOUT–B
14
VIN+B
VIN–B
VCMB
PIPELINE
14-BIT ADC
Integer 1-to-8 input clock divider
IF sampling frequencies to 250 MHz
DSYNC+B
DSYNC–B
−148.6 dBFS/Hz input noise at 180 MHz and 80 MSPS
−150.3 dBFS/Hz input noise at 180 MHz and 155 MSPS
Programmable internal ADC voltage reference
Flexible analog input range: 1.4 V p-p to 2.1 V p-p
ADC clock duty cycle stabilizer
REFERENCE
PLL
SERIAL PORT
1 TO 8
CLOCK
DIVIDER
PDWN
(SPI)
Serial port control
User-configurable, built-in self-test (BIST) capability
Energy-saving power-down modes
SCLK SDIO CSB
CLK+ CLK– SYNC
Figure 1. 48-Lead 7 mm × 7 mm LFCSP
APPLICATIONS
Communications
PRODUCT HIGHLIGHTS
Diversity radio systems
1. An on-chip PLL allows users to provide a single ADC
sampling clock; the PLL multiplies the ADC sampling
clock to produce the corresponding JESD204A data rate
clock.
2. The configurable JESD204A output block supports up to
1.6 Gbps per channel data rate when using a dedicated
data link per ADC or 3.2 Gbps data rate when using a
single shared data link for both ADCs.
3. Proprietary differential input that maintains excellent SNR
performance for input frequencies up to 250 MHz.
4. Operation from a single 1.8 V power supply.
5. Standard serial port interface (SPI) that supports various
product features and functions, such as data formatting
(offset binary, twos complement, or gray coding),
controlling the clock DCS, power-down, test modes,
voltage reference mode, and serial output configuration.
Multimode digital receivers (3G and 4G)
GSM, EDGE, W-CDMA, LTE,
CDMA2000, WiMAX, TD-SCDMA
I/Q demodulation systems
Smart antenna systems
General-purpose software radios
Broadband data applications
Ultrasound equipment
Rev. D
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice.
No license is granted by implication or otherwise under any patent or patent rights of Analog
Devices. Trademarks and registeredtrademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113 ©2010–2020 Analog Devices, Inc. All rights reserved.
AD9644
Data Sheet
TABLE OF CONTENTS
Features.............................................................................................. 1
Voltage Reference ...................................................................... 22
Clock Input Considerations ..................................................... 22
Channel/Chip Synchronization ............................................... 24
Power Dissipation and Standby Mode.................................... 24
Digital Outputs........................................................................... 24
Built-In Self-Test (BIST) and Output Test ................................. 29
Built-In Self-Test (BIST) ........................................................... 29
Output Test Modes.................................................................... 29
Serial Port Interface (SPI) ............................................................. 31
Configuration Using the SPI .................................................... 31
Hardware Interface .................................................................... 32
SPI Accessible Features ............................................................. 32
Memory Map .................................................................................. 33
Reading the Memory Map Register Table.............................. 33
Memory Map Register Table.................................................... 34
Memory Map Register Descriptions ....................................... 38
Applications Information ............................................................. 42
Design Guidelines ...................................................................... 42
Outline Dimensions....................................................................... 43
Ordering Guide .......................................................................... 43
Applications ...................................................................................... 1
Functional Block Diagram .............................................................. 1
Product Highlights........................................................................... 1
Revision History ............................................................................... 2
General Description......................................................................... 3
Specifications .................................................................................... 4
ADC DC Specifications............................................................... 4
ADC AC Specifications ............................................................... 5
Digital Specifications ................................................................... 6
Switching Specifications.............................................................. 8
Timing Specifications .................................................................. 9
Absolute Maximum Ratings ......................................................... 10
Thermal Characteristics ................................................................ 10
ESD Caution................................................................................ 10
Pin Configuration and Function Descriptions .......................... 11
Typical Performance Characteristics........................................... 13
Equivalent Circuits......................................................................... 19
Theory of Operation ...................................................................... 20
ADC Architecture ...................................................................... 20
Analog Input Considerations ................................................... 20
REVISION HISTORY
9/2020—Rev. C to Rev. D
4/2011—Rev. 0 to Rev. A
Changed CP-48-8 to CP-48-9......................................Throughout
Updated Outline Dimensions....................................................... 43
Changes to Ordering Guide.......................................................... 43
Added Model -155 ........................................................ Throughout
Changes to Features Section and Figure 1.....................................1
Changes to General Description Section .......................................3
Changes to Table 1............................................................................4
Changes to Table 2............................................................................5
Changes to Table 4............................................................................8
Additions to TPC Introductory Statement................................. 13
Changes to Speed Grade ID Bits in Table 17 ............................. 31
Changes to Ordering Guide.......................................................... 40
1/2012—Rev. B to Rev. C
Change to General Description Section........................................ 3
6/2011—Rev. A to Rev. B
Added Figure 23 to Figure 40; Renumbered Sequentially........ 16
Changes to Clock Input Considerations Section....................... 22
Added Figure 61 ............................................................................. 24
Changes to Digital Outputs and Timing Section....................... 27
Added Figure 69 ............................................................................. 28
Changes to Output Test Modes Section...................................... 29
Changes to SPI Accessible Features Section............................... 32
6/2010—Revision 0: Initial Version
Rev. D | Page 2 of 44
Data Sheet
AD9644
GENERAL DESCRIPTION
The AD9644 is a dual, 14-bit, analog-to-digital converter (ADC)
with a high speed serial output interface and sampling speeds
of either 80 MSPS or 155 MSPS.
By default, the ADC output data is routed directly to the two
external JESD204A serial output ports. These outputs are at CML
voltage levels. Two modes are supported such that output
coded data is either sent through one data link or two. (L = 1; F
= 4 or
L = 2; F = 2). Independent synchronization inputs (DSYNC)
are provided for each channel.
The AD9644 is designed to support communications appli-
cations where high performance, combined with low cost, small
size, and versatility, is desired. The JESD204A high speed serial
interface reduces board routing requirements and lowers pin count
requirements for the receiving device.
Flexible power-down options allow significant power savings,
when desired.
The dual ADC core features a multistage, differential pipelined
architecture with integrated output error correction logic. Each
ADC features wide bandwidth differential sample-and-hold
analog input amplifiers that support a variety of user-selectable
input ranges. An integrated voltage reference eases design consid-
erations. A duty cycle stabilizer is provided to compensate for
variations in the ADC clock duty cycle, allowing the converters
to maintain excellent performance.
Programming for setup and control is accomplished using a 3-wire
SPI-compatible serial interface.
The AD9644 is available in a 48-lead LFCSP and is specified over
the industrial temperature range of −40°C to +85°C.
This product is protected by a U.S. patent.
Rev. D | Page 3 of 44
AD9644
Data Sheet
SPECIFICATIONS
ADC DC SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, 1.75 V p-p differential input, VIN = −1.0 dBFS differential input, DCS enabled,
unless otherwise noted.
Table 1.
AD9644-80
Typ
AD9644-155
Typ
Parameter
Temperature Min
Max
Min
Max
Unit
RESOLUTION
Full
14
14
Bits
ACCURACY
No Missing Codes
Offset Error
Gain Error
Full
Full
Full
Full
±5°C
Full
±5°C
Guaranteed
±±
−±.5
Guaranteed
±±.±
−1.5
±1ꢀ
+1
±ꢀ.55
±11
+4
±ꢀ.55
mV
% FSR
LSB
LSB
LSB
−7
−6
Differential Nonlinearity (DNL)1
±ꢀ.3
±ꢀ.5
±ꢀ.3
Integral Nonlinearity (INL)1
±1.1
±1.±5
±ꢀ.55
LSB
MATCHING CHARACTERISTIC
Offset Error
Gain Error
Full
Full
−7
−1.5
+1.5
+ꢀ.6
+1ꢀ
+±.75
−6
−3.1
+1.5
+ꢀ.75
+9
+5
mV
% FSR
TEMPERATURE DRIFT
Offset Error
Gain Error
Full
Full
±5°C
±±
±35
ꢀ.7
±±
±144
ꢀ.7
ppm/°C
ppm/°C
LSB rms
INPUT REFERRED NOISE
ANALOG INPUT
Input Span
Input Capacitance±
Input Resistance
VCM OUTPUT LEVEL
POWER SUPPLIES
Supply Voltage
AVDD
Full
Full
Full
Full
1.383
ꢀ.88
1.75
7
±ꢀ
±.ꢀ87
ꢀ.9±
1.383
ꢀ.87
1.75
5
±ꢀ
±.ꢀ87
ꢀ.93
V p-p
pF
kΩ
V
ꢀ.9
ꢀ.9
Full
Full
1.7
1.7
1.8
1.8
1.9
1.9
1.7
1.7
1.8
1.8
1.9
1.9
V
V
DRVDD
Supply Current
IAVDD1
IDRVDD1
Full
Full
175
6ꢀ
19ꢀ
67
±±6
89
±4±
97
mA
mA
POWER CONSUMPTION
Sine Wave Input1
Standby Power3
Power-Down Power
Full
Full
Full
4±3
85
15
46ꢀ
±7
567
168
18
61ꢀ
±7
mW
mW
mW
1 Measured with a low input frequency, full-scale sine wave.
± Input capacitance refers to the effective capacitance between one differential input pin and AGND.
3 Standby power is measured with a dc input and with the CLK pins inactive (set to AVDD or AGND).
Rev. D | Page 4 of 44
Data Sheet
AD9644
ADC AC SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, 1.75 V p-p differential input, VIN = −1.0 dBFS differential input, DCS enabled,
unless otherwise noted.
Table 2.
AD9644-80
Typ
AD9644-155
Parameter1
Temperature
Min
Max
Min
Typ
Max
Unit
SIGNAL-TO-NOISE-RATIO (SNR)
fIN = 1ꢀ MHz
fIN = 7ꢀ MHz
±5°C
±5°C
±5°C
Full
73.8
73.7
7±.6
71.9
71.7
71.4
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
fIN = 18ꢀ MHz
71.8
7ꢀ.ꢀ
AD9644BCPZ-8ꢀ
AD9644CCPZ-8ꢀ
AD9644BCPZ-155
fIN = ±±ꢀ MHz
Full
Full
69.8
±5°C
7±.ꢀ
71.ꢀ
SIGNAL-TO-NOISE AND DISTORTION (SINAD)
fIN = 1ꢀ MHz
fIN = 7ꢀ MHz
±5°C
±5°C
±5°C
Full
7±.7
7±.6
71.5
7ꢀ.8
7ꢀ.7
7ꢀ.3
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
fIN = 18ꢀ MHz
7ꢀ.4
68.6
AD9644BCPZ-8ꢀ
AD9644CCPZ-8ꢀ
AD9644BCPZ-155
fIN = ±±ꢀ MHz
Full
Full
68.7
±5°C
71.1
69.9
EFFECTIVE NUMBER OF BITS (ENOB)
fIN = 1ꢀ MHz
fIN = 7ꢀ MHz
fIN = 18ꢀ MHz
fIN = ±±ꢀ MHz
±5°C
±5°C
±5°C
±5°C
11.8
11.8
11.6
11.5
11.5
11.5
11.4
11.3
Bits
Bits
Bits
Bits
WORST SECOND OR THIRD HARMONIC
fIN = 1ꢀ MHz
fIN = 7ꢀ MHz
±5°C
±5°C
±5°C
Full
−94
−9±
−87
−94
−9±
−9±
dBc
dBc
dBc
dBc
dBc
dBc
dBc
fIN = 18ꢀ MHz
−8ꢀ
−73
AD9644BCPZ-8ꢀ
AD9644CCPZ-8ꢀ
AD9644BCPZ-155
fIN = ±±ꢀ MHz
Full
Full
−8ꢀ
±5°C
−85
−9ꢀ
SPURIOUS-FREE DYNAMIC RANGE (SFDR)
fIN = 1ꢀ MHz
fIN = 7ꢀ MHz
±5°C
±5°C
±5°C
Full
94
9±
87
94
9±
9±
dBc
dBc
dBc
dBc
dBc
dBc
dBc
fIN = 18ꢀ MHz
8ꢀ
73
AD9644BCPZ-8ꢀ
AD9644CCPZ-8ꢀ
AD9644BCPZ-155
fIN = ±±ꢀ MHz
Full
Full
8ꢀ
±5°C
85
9ꢀ
WORST OTHER (HARMONIC OR SPUR)
fIN = 1ꢀ MHz
fIN = 7ꢀ MHz
±5°C
±5°C
±5°C
Full
−98
−98
−96
−97
−97
−95
dBc
dBc
dBc
dBc
dBc
dBc
dBc
fIN = 18ꢀ MHz
−9ꢀ
−87
AD9644BCPZ-8ꢀ
AD9644CCPZ-8ꢀ
AD9644BCPZ-155
fIN = ±±ꢀ MHz
Full
Full
−89
±5°C
−95
−94
Rev. D | Page 5 of 44
AD9644
Data Sheet
AD9644-80
Typ
AD9644-155
Parameter1
Temperature
Min
Max
Min
Typ
Max
Unit
TWO-TONE SFDR
fIN = +3ꢀ MHz (−7 dBFS ), +33 MHz (−7 dBFS )
fIN = +169 MHz (−7 dBFS ), +17± MHz (−7 dBFS )
CROSSTALK±
±5°C
±5°C
Full
93
89
9ꢀ
89
dBc
dBc
dB
−1ꢀ5
78ꢀ
−1ꢀ5
78ꢀ
ANALOG INPUT BANDWIDTH3
±5°C
MHz
1 See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for a complete set of definitions.
± Crosstalk is measured at 1ꢀꢀ MHz with −1.ꢀ dBFS on one channel and no input on the alternate channel.
3 Analog input bandwidth specifies the −3 dB input BW of the AD9644 input. The usable full-scale BW of the part with good performance is ±5ꢀ MHz.
DIGITAL SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, 1.75 V p-p differential input, VIN = −1.0 dBFS differential input, and DCS enabled,
unless otherwise noted.
Table 3.
AD9644-80/AD9644-155
Parameter
Temperature
Min
Typ
Max
Unit
DIFFERENTIAL CLOCK INPUTS (CLK+, CLK−)
Logic Compliance
CMOS/LVDS/LVPECL
ꢀ.9
Internal Common-Mode Bias
Differential Input Voltage
Input Voltage Range
Input Common-Mode Range
High Level Input Current
Low Level Input Current
Input Capacitance
Full
Full
Full
Full
Full
Full
Full
Full
V
ꢀ.3
AGND
ꢀ.9
−1ꢀꢀ
−1ꢀꢀ
3.6
AVDD
1.4
V p-p
V
V
+1ꢀꢀ
+1ꢀꢀ
μA
μA
pF
kΩ
4
1ꢀ
Input Resistance
8
1±
SYNC INPUT
Logic Compliance
Internal Bias
CMOS
ꢀ.9
Full
Full
Full
Full
Full
Full
Full
Full
V
Input Voltage Range
High Level Input Voltage
Low Level Input Voltage
High Level Input Current
Low Level Input Current
Input Capacitance
AGND
1.±
AGND
−1ꢀꢀ
−1ꢀꢀ
AVDD
AVDD
ꢀ.6
V
V
V
+1ꢀꢀ
+1ꢀꢀ
μA
μA
pF
kΩ
1
16
Input Resistance
1±
±ꢀ
DSYNC INPUT
Logic Compliance
Internal Bias
CMOS/LVDS
ꢀ.9
Full
Full
Full
Full
Full
Full
Full
Full
V
Input Voltage Range
High Level Input Voltage
Low Level Input Voltage
High Level Input Current
Low Level Input Current
Input Capacitance
AGND
1.±
AGND
−1ꢀꢀ
−1ꢀꢀ
AVDD
AVDD
ꢀ.6
V
V
V
+1ꢀꢀ
+1ꢀꢀ
μA
μA
pF
kΩ
1
16
Input Resistance
1±
±ꢀ
Rev. D | Page 6 of 44
Data Sheet
AD9644
AD9644-80/AD9644-155
Parameter
LOGIC INPUT (CSB)1
Temperature
Min
Typ
Max
Unit
Logic Compliance
CMOS
High Level Input Voltage
Low Level Input Voltage
High Level Input Current
Low Level Input Current
Input Resistance
Full
Full
Full
Full
Full
Full
1.±±
ꢀ
−1ꢀ
4ꢀ
±.1
ꢀ.6
+1ꢀ
13±
V
V
μA
μA
kΩ
pF
±6
±
Input Capacitance
LOGIC INPUT (SCLK, PDWN)±
Logic Compliance
CMOS
High Level Input Voltage
Low Level Input Voltage
High Level Input Current (VIN = 1.8 V)
Low Level Input Current
Input Resistance
Full
Full
Full
Full
Full
Full
1.±±
ꢀ
−9±
−1ꢀ
±.1
ꢀ.6
−135
+1ꢀ
V
V
μA
μA
kΩ
pF
±6
±
Input Capacitance
LOGIC INPUT/OUTPUT (SDIO)1
Logic Compliance
CMOS
High Level Input Voltage
Low Level Input Voltage
High Level Input Current
Low Level Input Current
Input Resistance
Full
Full
Full
Full
Full
Full
1.±±
ꢀ
−1ꢀ
38
±.1
ꢀ.6
+1ꢀ
1±8
V
V
μA
μA
kΩ
pF
±6
5
Input Capacitance
DIGITAL OUTPUTS
Logic Compliance
Differential Output Voltage (VOD)
Output Offset Voltage (VOS)
Full
Full
Full
CML
ꢀ.8
DRVDD/±
ꢀ.6
ꢀ.75
1.1
1.ꢀ5
V
V
1 Pull up.
± Pull down.
Rev. D | Page 7 of 44
AD9644
Data Sheet
SWITCHING SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, 1.75 V p-p differential input, VIN = −1.0 dBFS differential input, and DCS enabled,
unless otherwise noted.
Table 4.
AD9644-80
Typ
AD9644-155
Typ
Parameter
Temperature Min
Max Min
Max
Unit
CLOCK INPUT PARAMETERS
Input Clock Rate
Full
Full
Full
64ꢀ
8ꢀ
64ꢀ
155
MHz
MSPS
ns
Conversion Rate1
4ꢀ
1±.5
4ꢀ
6.45
CLK Period—Divide-by-1 Mode (tCLK
)
CLK Pulse Width High (tCH)
Divide-by-1 Mode, DCS Enabled
Divide-by-1 Mode, DCS Disabled
Divide-by-± Mode Through Divide-by-8
Mode
Full
Full
Full
3.75
5.95
ꢀ.8
6.±5
6.±5
8.75
6.55
1.935
3.ꢀ65
ꢀ.8
3.±±5
3.±±5
4.515 ns
3.385 ns
ns
Aperture Delay (tA)
Full
Full
ꢀ.78
ꢀ.1±5
ꢀ.78
ꢀ.1±5
ns
ps rms
Aperture Uncertainty (Jitter, tJ)
DATA OUTPUT PARAMETERS
Data Output Period or UI (Unit Interval)
Data Output Duty Cycle
Data Valid Time
PLL Lock Time (tLOCK
Wake Up Time (Standby)
Wake Up Time (Power-Down)±
Pipeline Delay (Latency)
Full
1/(±ꢀ × fCLK
)
1/(±ꢀ × fCLK
)
Seconds
%
UI
μs
μs
ms
5ꢀ
ꢀ.78
4
±5°C
±5°C
±5°C
±5°C
±5°C
Full
5ꢀ
ꢀ.74
4
5
±.5
)
5
±.5
±3
±4
±3
±4
CLK
cycles
Data Rate per Channel (NRZ)
Deterministic Jitter
Random Jitter at 1.6 Gbps
Random Jitter at 3.± Gbps
Output Rise/Fall Time
±5°C
±5°C
±5°C
±5°C
±5°C
1.6
4ꢀ
9.5
5.±
5ꢀ
3.1
4ꢀ
Gbps
ps
ps rms
ps rms
ps
5.±
5ꢀ
TERMINATION CHARACTERISTICS
Differential Termination Resistance
OUT-OF-RANGE RECOVERY TIME
±5°C
±5°C
1ꢀꢀ
±
1ꢀꢀ
±
Ω
CLK
cycles
1 Conversion rate is the clock rate after the divider.
± Wake-up time is defined as the time required to return to normal operation from power-down mode.
Rev. D | Page 8 of 44
Data Sheet
AD9644
TIMING SPECIFICATIONS
Table 5.
Parameter
Conditions
Limit
SYNC TIMING REQUIREMENTS
tSSYNC
tHSYNC
SYNC to rising edge of CLK+ setup time
SYNC to rising edge of CLK+ hold time
ꢀ.3ꢀ ns typ
ꢀ.3ꢀ ns typ
SPI TIMING REQUIREMENTS
tDS
tDH
tCLK
tS
tH
tHIGH
tLOW
tEN_SDIO
Setup time between the data and the rising edge of SCLK
Hold time between the data and the rising edge of SCLK
Period of the SCLK
Setup time between CSB and SCLK
Hold time between CSB and SCLK
SCLK pulse width high
± ns min
± ns min
4ꢀ ns min
± ns min
± ns min
1ꢀ ns min
1ꢀ ns min
1ꢀ ns min
SCLK pulse width low
Time required for the SDIO pin to switch from an input to an output relative to the SCLK
falling edge
tDIS_SDIO
Time required for the SDIO pin to switch from an output to an input relative to the SCLK
rising edge
1ꢀ ns min
Timing Diagrams
SAMPLE
N
N – 23
ANALOG
N – 22
N + 1
INPUT
N – 21
SIGNAL
N – 1
N – 20
CLK–
CLK+
CLK–
CLK+
DOUT+
DOUT–
SAMPLE N – 23
ENCODED INTO 2
8b/10b SYMBOLS
SAMPLE N – 22
ENCODED INTO 2
8b/10b SYMBOLS
SAMPLE N – 21
ENCODED INTO 2
8b/10b SYMBOLS
Figure 2. Data Output Timing
CLK+
SYNC
tSSYNC
tHSYNC
Figure 3. SYNC Input Timing Requirements
Rev. D | Page 9 of 44
AD9644
Data Sheet
ABSOLUTE MAXIMUM RATINGS
THERMAL CHARACTERISTICS
Table 6.
The exposed paddle must be soldered to the ground plane for
the LFCSP package. Soldering the exposed paddle to the PCB
increases the reliability of the solder joints and maximizes the
thermal capability of the package.
Parameter
Rating
ELECTRICAL
AVDD to AGND
DRVDD to AGND
−ꢀ.3 V to +±.ꢀ V
−ꢀ.3 V to +±.ꢀV
VIN+A/VIN+B, VIN−A/VIN−B to AGND −ꢀ.3 V to AVDD + ꢀ.± V
Table 7. Thermal Resistance
CLK+, CLK− to AGND
SYNC to AGND
VCMA, VCMB to AGND
CSB to AGND
SCLK to AGND
SDIO to AGND
PDWN to AGND
DOUT+A, DOUTꢀ−A, DOUTꢀ+B,
DOUT−B to AGND
−ꢀ.3 V to AVDD + ꢀ.± V
−ꢀ.3 V to AVDD + ꢀ.± V
−ꢀ.3 V to AVDD + ꢀ.± V
−ꢀ.3 V to DRVDD + ꢀ.± V
−ꢀ.3 V to DRVDD + ꢀ.± V
−ꢀ.3 V to DRVDD + ꢀ.± V
−ꢀ.3 V to DRVDD + ꢀ.± V
−ꢀ.3 V to DRVDD + ꢀ.± V
Airflow
Velocity
(m/sec)
1, 2
1, 3
1, 4
Package Type
θJA
±5
±±
±ꢀ
θJC
θJB
Unit
°C/W
°C/W
°C/W
48-Lead LFCSP
7 mm × 7 mm
(CP-48-9)
ꢀ
±
14
1.ꢀ
±.5
1 Per JEDEC 51-7, plus JEDEC ±5-5 ±S±P test board.
± Per JEDEC JESD51-± (still air) or JEDEC JESD51-6 (moving air).
3 Per MIL-STD 883, Method 1ꢀ1±.1.
4 Per JEDEC JESD51-8 (still air).
DSYNC+A, DSYNC−A, DSYNC+B,
DSYNC−B to AGND
−ꢀ.3 V to DRVDD + ꢀ.± V
Typical θJA is specified for a 4-layer PCB with a solid ground
plane. As shown Table 7, airflow improves heat dissipation,
which reduces θJA. In addition, metal in direct contact with the
package leads from metal traces, through holes, ground, and
power planes, reduces θJA.
ENVIRONMENTAL
Operating Temperature Range
(Ambient)
Maximum Junction Temperature
Under Bias
−4ꢀ°C to +85°C
15ꢀ°C
Storage Temperature Range
(Ambient)
−65°C to +15ꢀ°C
ESD CAUTION
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Rev. D | Page 1ꢀ of 44
Data Sheet
AD9644
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
1
2
3
36 VCMA
DNC
34 DNC
VCMB
AVDD
DNC
35
4
5
6
7
8
9
10
11
12
AVDD
CLK+
CLK–
AVDD
SYNC
AVDD
DRGND
DRVDD
DNC
33 PDWN
AD9644
TOP
VIEW
32
31
30
29
DNC
CSB
SCLK
SDIO
(Not to Scale)
28 DRVDD
27 DRVDD
26
DRGND
25 DNC
NOTES
1. DNC = DO NOT CONNECT.
2. THE EXPOSED THERMAL PAD ON THE BOTTOM OF THE PACKAGE
PROVIDES THE ANALOG GROUND FOR THE PART. THIS EXPOSED PAD
MUST BE CONNECTED TO GROUND FOR PROPER OPERATION.
Figure 4. LFCSP Pin Configuration (Top View)
Table 8. Pin Function Descriptions
Pin No.
Mnemonic
Type
Description
ADC Power Supplies
11, 15, ±±, ±7, ±8
±, 4, 7, 9, 37, 38, 41,
4±, 43, 44, 47, 48
DRVDD
AVDD
Supply
Supply
Digital Output Driver Supply (1.8 V Nominal).
Analog Power Supply (1.8 V Nominal).
3, 1±, ±5, 3±, 34, 35
1ꢀ, 16, ±1, ±6
DNC
DRGND
Do Not Connect.
Digital Driver Supply Ground.
Driver
Ground
ꢀ
AGND,
Exposed Pad
Ground
The exposed thermal pad on the bottom of the package provides the analog
ground for the part. This exposed pad must be connected to ground for
proper operation.
ADC Analog
4ꢀ
39
45
46
36
1
5
6
VIN+A
VIN−A
VIN+B
VIN−B
VCMA
VCMB
CLK+
Input
Input
Input
Input
Output
Output
Input
Input
Differential Analog Input Pin (+) for Channel A.
Differential Analog Input Pin (−) for Channel A.
Differential Analog Input Pin (+) for Channel B.
Differential Analog Input Pin (−) for Channel B.
Common-Mode Level Bias Output for Channel A Analog Input.
Common-Mode Level Bias Output for Channel B Analog Input.
ADC Clock Input—True.
CLK−
ADC Clock Input—Complement.
Digital Input
8
±4
SYNC
DSYNC+A
Input
Input
Input Clock Divider Synchronization Pin.
Active Low JESD±ꢀ4A LVDS Channel A SYNC Input—True/JESD±ꢀ4A CMOS
Channel A SYNC Input.
±3
14
DSYNC−A
DSYNC+B
Input
Input
Active Low JESD±ꢀ4A LVDS Channel A SYNC Input—Complement.
Active Low JESD±ꢀ4A LVDS Channel B SYNC Input—True/JESD±ꢀ4A CMOS
Channel A SYNC Input.
13
DSYNC−B
Input
Active Low JESD±ꢀ4A LVDS Channel B SYNC Input—Complement.
Rev. D | Page 11 of 44
AD9644
Data Sheet
Pin No.
Mnemonic
Type
Description
Digital Outputs
±ꢀ
19
18
17
DOUT+A
DOUT−A
DOUT+B
DOUT−B
Output
Output
Output
Output
Channel A CML Output Data—True.
Channel A CML Output Data—Complement.
Channel B CML Output Data—True.
Channel B CML Output Data—Complement.
SPI Control
3ꢀ
±9
31
SCLK
SDIO
CSB
Input
SPI Serial Clock.
Input/Output SPI Serial Data Input/Output.
Input
Input
SPI Chip Select (Active Low).
ADC Configuration
33
PDWN
Power-Down Input. Using the SPI interface, this input can be configured as
power-down or standby.
Rev. D | Page 1± of 44
Data Sheet
AD9644
TYPICAL PERFORMANCE CHARACTERISTICS
AVDD = 1.8 V, DRVDD = 1.8 V, DCS enabled, 1.75 V p-p differential input, VIN = −1.0 dBFS, and 32k sample,
TA = 25°C, unless otherwise noted.
0
–20
0
80MSPS
80MSPS
10.1MHz @ –1dBFS
SNR = 73.0dB (74.0dBFS)
SFDR = 95dBc
140.3MHz @ –1dBFS
SNR = 72.2dB (73.2dBFS)
SFDR = 94.0dBc
–20
–40
–40
–60
–60
–80
–80
THIRD HARMONIC
–100
–120
–140
–100
–120
–140
0
10
20
30
40
40
40
0
10
20
FREQUENCY (MHz)
30
40
FREQUENCY (MHz)
Figure 5. AD9644-80 Single-Tone FFT with fIN = 10.1 MHz
Figure 8. AD9644-80 Single-Tone FFT with fIN = 140.1 MHz
0
0
80MSPS
80MSPS
30.1MHz @ –1dBFS
SNR = 72.7dB (73.7dBFS)
SFDR = 94dBc
180.1MHz @ –1dBFS
SNR = 71.6dB (72.6dBFS)
SFDR = 93dBc
–20
–40
–20
–40
–60
–60
SECOND HARMONIC
SECOND HARMONIC
THIRD HARMONIC
–80
–80
–100
–120
–140
–100
–120
–140
0
10
20
FREQUENCY (MHz)
30
0
10
20
FREQUENCY (MHz)
30
40
Figure 6. AD9644-80 Single-Tone FFT with fIN = 30.1 MHz
Figure 9. AD9644-80 Single-Tone FFT with fIN = 180.1 MHz
0
0
80MSPS
80MSPS
70.1MHz @ –1dBFS
SNR = 72.5dB (73.5dBFS)
SFDR = 94.0dBc
220.1MHz @ –1dBFS
SNR = 71.1dB (72.1dBFS)
SFDR = 92dBc
–20
–40
–20
–40
–60
–60
THIRD HARMONIC
SECOND HARMONIC
SECOND HARMONIC
THIRD HARMONIC
–80
–80
–100
–120
–140
–100
–120
–140
0
10
20
FREQUENCY (MHz)
30
0
10
20
FREQUENCY (MHz)
30
40
Figure 7. AD9644-80 Single-Tone FFT with fIN = 70.1 MHz
Figure 10. AD9644-80 Single-Tone FFT with fIN = 220.1 MHz
Rev. D | Page 13 of 44
AD9644
Data Sheet
100
95
90
85
80
75
70
65
120
100
80
60
40
20
0
SNR @ –40°C
SFDR @ –40°C
SNR @ +25°C
SFDR @ +25°C
SNR @ +85°C
SFDR @ +85°C
SFDR (dBFS)
SFDR (dBc)
SNR (dBFS)
SNR (dBc)
0
50
100
150
200
250
INPUT FREQUENCY (MHz)
INPUT AMPLITUDE (dBFS)
Figure 14. AD9644-80 Single-Tone SNR/SFDR vs. Input Frequency (fIN) and
Temperature with 2.0 V p-p Full-Scale, fS = 80 MSPS
Figure 11. AD9644-80 Single-Tone SNR/SFDR vs. Input Amplitude (AIN
)
with fIN = 10.1 MHz, fS = 80 MSPS
0
120
100
80
–20
–40
SFDR (dBFS)
SFDR (dBc)
SNR (dBFS)
SNR (dBc)
–60
–80
SFDR (dBc)
IMD3 (dBc)
SFDR (dBFS)
IMD3 (dBFS)
60
40
20
–100
–120
0
–90
–78
–66
–54
–42
–30
–18
–6
INPUT AMPLITUDE (dBFS)
INPUT AMPLITUDE (dBFS)
Figure 12. AD9644-80 Single-Tone SNR/SFDR vs. Input Amplitude (AIN
)
Figure 15. AD9644-80 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN
)
with fIN = 180 MHz, fS = 80 MSPS
with fIN1 = 29.9 MHz, fIN2 = 32.9 MHz, fS = 80 MSPS
100
95
0
–20
–40
90
SNR @ –40°C
SFDR @ –40°C
85
SNR @ +25°C
SFDR @ +25°C
SNR @ +85°C
SFDR @ +85°C
–60
–80
SFDR (dBc)
IMD3 (dBc)
SFDR (dBFS)
IMD3 (dBFS)
80
75
70
65
–100
–120
0
50
100
150
200
250
–90
–78
–66
–54
–42
–30
–18
–6
INPUT FREQUENCY (MHz)
INPUT AMPLITUDE (dBFS)
Figure 13. AD9644-80 Single-Tone SNR/SFDR vs. Input Frequency (fIN) and
Temperature with 1.75 V p-p Full-Scale, fS = 80 MSPS
Figure 16. AD9644-80 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN
)
with fIN1 = 169.1 MHz, fIN2 = 172.1 MHz, fS = 80 MSPS
Rev. D | Page 14 of 44
Data Sheet
AD9644
0
14,000
12,000
10,000
8000
80MSPS
29.9MHz @ –7dBFS
32.9MHz @ –7dBFS
SFDR = 94.4dBc (101.4dBFS)
–20
–40
–60
6000
–80
4000
–100
–120
–140
2000
0
0
10
20
FREQUENCY (MHz)
30
40
N – 4 N – 3 N – 2 N – 1
N
N + 1 N + 2 N + 3 N + 4
OUTPUT CODE
Figure 17. AD9644-80 Two-Tone FFT with fIN1 = 29.9 MHz and fIN2 = 32.9 MHz
Figure 20. AD9644-80 Grounded Input Histogram
0
1.0
0.8
80MSPS
169.1MHz @ –7dBFS
–20
–40
172.1MHz @ –7dBFS
SFDR = 91.9dBc (98.9dBFS)
0.6
0.4
0.2
–60
0
–80
–0.2
–0.4
–0.6
–0.8
–1.0
–100
–120
–140
0
10
20
FREQUENCY (MHz)
30
40
0
200
400
600
800
1000 1200 1400 1600
OUTPUT CODE
Figure 18. AD9644-80 Two-Tone FFT with fIN1 = 169.1 MHz and
fIN2 = 172.1 MHz
Figure 21. AD9644-80 INL with fIN = 30.3 MHz
100
0.50
0.25
0
95
90
85
80
75
70
SNR CHANNEL B
SFDR CHANNEL B
SNR CHANNEL A
SFDR CHANNEL A
–0.25
–0.50
45
50
55
60
65
70
75
80
0
2000 4000 6000 8000 10,000 12,000 14,000 16,000
OUTPUT CODE
SAMPLE RATE (MSPS)
Figure 19. AD9644-80 Single-Tone SNR/SFDR vs. Sample Rate (fS)
with fIN = 70. MHz
Figure 22. AD9644-80 DNL with fIN = 30.3 MHz
Rev. D | Page 15 of 44
AD9644
Data Sheet
0
–20
–40
–60
0
–20
–40
–60
155MSPS
155MSPS
10.1MHz @ –1dBFS
SNR = 70.9dB (71.9dBFS)
SFDR = 94dBc
140.1MHz @ –1dBFS
SNR = 70.5dB (71.5dBFS)
SFDR = 92dBc
SECOND HARMONIC
THIRD HARMONIC
THIRD HARMONIC
–80
–100
–120
–80
–100
–120
–140
–140
0
7.75 15.50 23.25 31.00 38.75 46.50 54.25 62.00 69.75 77.50
FREQUENCY (MHz)
0
7.75 15.50 23.25 31.00 38.75 46.50 54.25 62.00 69.75 77.50
FREQUENCY (MHz)
Figure 23. AD9644-155 Single-Tone FFT with fIN = 10.1 MHz
Figure 26. AD9644-155 Single-Tone FFT with fIN = 140.1 MHz
0
0
155MSPS
155MSPS
30.1MHz @ –1dBFS
SNR = 70.8dB (71.8dBFS)
SFDR = 93dBc
180.1MHz @ –1dBFS
SNR = 70.4dB (71.4dBFS)
SFDR = 92dBc
–20
–20
–40
–60
–40
–60
THIRD
HARMONIC
THIRD HARMONIC
SECOND
HARMONIC
–80
–100
–120
–140
–80
–100
–120
–140
0
7.75 15.50 23.25 31.00 38.75 46.50 54.25 62.00 69.75 77.50
FREQUENCY (MHz)
0
7.75 15.50 23.25 31.00 38.75 46.50 54.25 62.00 69.75 77.50
FREQUENCY (MHz)
Figure 24. AD9644-155 Single-Tone FFT with fIN = 30.1 MHz
Figure 27. AD9644-155 Single-Tone FFT with fIN = 180.1 MHz
0
0
155MSPS
155MSPS
70.1MHz @ –1dBFS
SNR = 70.7dB (71.7dBFS)
SFDR = 92dBc
220.1MHz @ –1dBFS
SNR = 70.0dB (71.0dBFS)
SFDR = 90dBc
–20
–20
–40
–60
–40
–60
THIRD HARMONIC
–80
–100
–120
–140
–80
–100
–120
–140
0
7.75 15.50 23.25 31.00 38.75 46.50 54.25 62.00 69.75 77.50
FREQUENCY (MHz)
0
7.75 15.50 23.25 31.00 38.75 46.50 54.25 62.00 69.75 77.50
FREQUENCY (MHz)
Figure 25. AD9644-155 Single-Tone FFT with fIN = 70.1 MHz
Figure 28. AD9644-155 Single-Tone FFT with fIN = 220.1 MHz
Rev. D | Page 16 of 44
Data Sheet
AD9644
120
100
80
60
40
20
0
100
95
SNR @ –40°C
SFDR (dBFS)
SNR (dBFS)
SFDR @ –40°C
SNR @ +25°C
SFDR @ +25°C
SNR @ +85°C
SFDR @ +85°C
90
85
SFDR (dBc)
80
75
70
65
SNR (dBc)
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
0
50
100
150
200
250
300
INPUT AMPLITUDE (dBFS)
INPUT FREQUENCY (MHz)
Figure 29. AD9644-155 Single-Tone SNR/SFDR vs. Input Amplitude (AIN
)
Figure 32. AD9644-155 Single-Tone SNR/SFDR vs. Input Frequency (fIN) and
Temperature with 2.0 V p-p Full-Scale, fS = 80 MSPS
with fIN = 10.1 MHz, fS = 80 MSPS
120
0
–20
–40
SFDR (dBFS)
100
80
SNR (dBFS)
SFDR (dBc)
60
–60
SFDR (dBc)
IMD3 (dBc)
40
–80
SNR (dBc)
20
–100
SFDR (dBFS)
IMD3 (dBFS)
0
–90
–120
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
–78
–66
–54
–42
–30
–18
–6
INPUT AMPLITUDE (dBFS)
INPUT AMPLITUDE (dBFS)
Figure 30. AD9644-155 Single-Tone SNR/SFDR vs. Input Amplitude (AIN
)
Figure 33. AD9644-155 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN
)
with fIN = 180 MHz, fS = 80 MSPS
with fIN1 = 29.9 MHz, fIN2 = 32.9 MHz, fS = 80 MSPS
100
95
0
–20
–40
90
SNR @ –40°C
SFDR @ –40°C
SNR @ +25°C
SFDR @ +25°C
SNR @ +85°C
SFDR @ +85°C
85
SFDR (dBc)
–60
IMD3 (dBc)
80
75
70
65
–80
SFDR (dBFS)
IMD3 (dBFS)
–100
–120
–90
–78
–66
–54
–42
–30
–18
–6
0
50
100
150
200
250
300
INPUT AMPLITUDE (dBFS)
INPUT FREQUENCY (MHz)
Figure 34. AD9644-155 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN
)
Figure 31. AD9644-155 Single-Tone SNR/SFDR vs. Input Frequency (fIN) and
Temperature with 1.75 V p-p Full-Scale, fS = 80 MSPS
with fIN1 = 169.1 MHz, fIN2 = 172.1 MHz, fS = 80 MSPS
Rev. D | Page 17 of 44
AD9644
Data Sheet
0
–20
–40
–60
4000
3500
155MSPS
29.9MHz @ –7dBFS
32.9MHz @ –7dBFS
SFDR = 89.8dBc (96.8dBFS)
3000
2500
2000
1500
–80
–100
–120
1000
500
0
–140
0
7.75 15.50 23.25 31.00 38.75 46.50 54.25 62.00 69.75 77.50
FREQUENCY (MHz)
N – 5 N – 4 N – 3 N – 2 N – 1
N
N + 1 N + 2 N + 3 N + 4 N + 5
OUTPUT CODE
Figure 35. AD9644-155 Two-Tone FFT with fIN1 = 29.9 MHz and fIN2 = 32.9 MHz
Figure 38. AD9644-155 Grounded Input Histogram
0
1
0.8
155MSPS
169.1MHz @ –7dBFS
–20
–40
–60
172.1MHz @ –7dBFS
SFDR = 89.1dBc (96.1dBFS)
0.6
0.4
0.2
0
–80
–100
–120
–140
–0.2
–0.4
–0.6
–0.8
–1
0
7.75 15.50 23.25 31.00 38.75 46.50 54.25 62.00 69.75 77.50
FREQUENCY (MHz)
0
2000 4000 6000
8000 10000 12000 14000 16000
OUTPUT CODE
Figure 36. AD9644-155 Two-Tone FFT with fIN1 = 169.1 MHz and
fIN2 = 172.1 MHz
Figure 39. AD9644-155 INL with fIN = 30.3 MHz
100
0.5
0.25
0
95
90
85
SNR, CHANNEL B
SFDR, CHANNEL B
SNR, CHANNEL A
80
SFDR, CHANNEL A
–0.25
–0.5
75
70
50
65
80
95
110
125
140
155
0
2000 4000 6000
8000 10000 12000 14000 16000
SAMPLE RATE (MSPS)
OUTPUT CODE
Figure 37. AD9644-155 Single-Tone SNR/SFDR vs. Sample Rate (fS)
with fIN = 70. MHz
Figure 40. AD9644-155 DNL with fIN = 30.3 MHz
Rev. D | Page 18 of 44
Data Sheet
AD9644
EQUIVALENT CIRCUITS
AVDD
350Ω
30kΩ
SCLK
OR
PDWN
VIN
Figure 41. Equivalent Analog Input Circuit
Figure 45. Equivalent SCLK or PDWN Input Circuit
AVDD
AVDD
AVDD
AVDD
30kΩ
350Ω
0.9V
CSB
15kΩ
15kΩ
CLK+
CLK–
Figure 42. Equivalent Clock Input Circuit
Figure 46. Equivalent CSB Input Circuit
DRVDD
AVDD
AVDD
4mA
4mA
4mA
4mA
R
TERM
V
DOUT±A/B
DOUT±A/B
DSYNC±A/B
OR SYNC
CM
0.9V
16kΩ
0.9V
Figure 43. Digital CML Output
Figure 47. Equivalent SYNC and DSYNC Input Circuit
DRVDD
350Ω
30kΩ
SDIO
Figure 44. Equivalent SDIO Circuit
Rev. D | Page 19 of 44
AD9644
Data Sheet
THEORY OF OPERATION
A small resistor in series with each input can help reduce the
peak transient current required from the output stage of the
driving source. A shunt capacitor can be placed across the
inputs to provide dynamic charging currents. This passive
network creates a low-pass filter at the ADC input; therefore,
the precise values are dependent on the application.
The AD9644 dual-core analog-to-digital converter (ADC) can
be used for diversity reception of signals, in which the ADCs are
operating identically on the same carrier but from two separate
antennae. The ADCs can also be operated with independent
analog inputs. The user can sample any fS/2 frequency segment
from dc to 250 MHz, using appropriate low-pass or band-pass
filtering at the ADC inputs with little loss in ADC performance.
In intermediate frequency (IF) undersampling applications, any
shunt capacitors or series resistors should be reduced since the
input sample capacitor is unbuffered. In combination with the
driving source impedance, the shunt capacitors limit the input
bandwidth. Refer to the AN-742 Application Note, Frequency
Domain Response of Switched-Capacitor ADCs; the AN-827
Application Note, A Resonant Approach to Interfacing Amplifiers
to Switched-Capacitor ADCs; and the Analog Dialog article,
“Transformer-Coupled Front-End for Wideband A/D
Converters,” for more information on this subject (refer to
www.analog.com).
In nondiversity applications, the AD9644 can be used as a base-
band or direct downconversion receiver, in which one ADC is
used for I input data, and the other is used for Q input data.
Synchronization capability is provided to allow synchronized
timing between multiple devices.
Programming and control of the AD9644 are accomplished
using a 3-wire SPI-compatible serial interface.
ADC ARCHITECTURE
The AD9644 architecture consists of a dual front-end sample-
and-hold circuit, followed by a pipelined, switched-capacitor
ADC. The quantized outputs from each stage are combined into
a final 14-bit result in the digital correction logic. The pipelined
architecture permits the first stage to operate on a new input
sample and the remaining stages to operate on the preceding
samples. Sampling occurs on the rising edge of the clock.
BIAS
S
S
C
FB
C
S
VIN+
VIN–
C
PAR1
C
PAR2
H
S
S
S
C
Each stage of the pipeline, excluding the last, consists of a low
resolution flash ADC connected to a switched-capacitor digital-
to-analog converter (DAC) and an interstage residue amplifier
(MDAC). The MDAC magnifies the difference between the
recon-structed DAC output and the flash input for the next
stage in the pipeline. One bit of redundancy is used in each stage
to facilitate digital correction of flash errors. The last stage simply
consists of a flash ADC.
S
C
FB
C
C
PAR1
PAR2
S
BIAS
Figure 48. Switched-Capacitor Input
For best dynamic performance, the source impedances driving
VIN+ and VIN− should be matched, and the inputs should be
differentially balanced.
The input stage of each channel contains a differential sampling
circuit that can be ac- or dc-coupled in differential or single-
ended modes. The output staging block aligns the data, corrects
errors, and passes the data to the output buffers. The output buffers
are powered from a separate supply, allowing digital output noise
to be separated from the analog core. During power-down, the
output buffers go into a high impedance state.
Input Common Mode
The analog inputs of the AD9644 are not internally dc biased.
In ac-coupled applications, the user must provide this bias
externally. Setting the device so that VCM = 0.5 × AVDD (or
0.9 V) is recommended for optimum performance. An on-
board common-mode voltage reference is included in the
design and is available from the VCMA and VCMB pins. Using
the VCMA and VCMB outputs to set the input common mode
is recommended. Optimum performance is achieved when the
common-mode voltage of the analog input is set by the VCMA
and VCMB pin voltages (typically 0.5 × AVDD). The VCMA
and VCMB pins must be decoupled to ground by a 0.1 μF
capacitor. This decoupling capacitor should be placed close
to the pin to minimize the series resistance and inductance
between the part and this capacitor.
ANALOG INPUT CONSIDERATIONS
The analog input to the AD9644 is a differential switched-
capacitor circuit that has been designed for optimum performance
while processing a differential input signal.
The clock signal alternatively switches the input between sample
mode and hold mode (see Figure 48). When the input is switched
into sample mode, the signal source must be capable of charging
the sample capacitors and settling within ½ of a clock cycle.
Rev. D | Page ±ꢀ of 44
Data Sheet
AD9644
The signal characteristics must be considered when selecting
Differential Input Configurations
a transformer. Most RF transformers saturate at frequencies
below a few megahertz (MHz). Excessive signal power can also
cause core saturation, which leads to distortion.
Optimum performance is achieved while driving the AD9644 in a
differential input configuration. For baseband applications, the
AD8138, ADA4937-2, and ADA4938-2 differential drivers provide
excellent performance and a flexible interface to the ADC.
At input frequencies in the second Nyquist zone and above, the
noise performance of most amplifiers is not adequate to achieve
the true SNR performance of the AD9644. For applications in
which SNR is a key parameter, differential double balun coupling
is the recommended input configuration (see Figure 51). In this
configuration, the input is ac-coupled and the VCM is provided
to each input through a 33 Ω resistor. These resistors compensate
for losses in the input baluns to provide a 50 Ω impedance to
the driver.
The output common-mode voltage of the ADA4938-2 is easily
set with the VCM pin of the AD9644 (see Figure 49), and the
driver can be configured in a Sallen-Key filter topology to
provide band limiting of the input signal.
15pF
200Ω
33Ω
5pF
15Ω
90Ω
VIN–
VIN+
AVDD
ADC
VCM
76.8Ω
VIN
In the double balun and transformer configurations, the value of
the input capacitors and resistors is dependent on the input fre-
quency and source impedance. Based on these parameters the
value of the input resistors and capacitors may need to be
adjusted or some components may need to be removed. Table 9
displays recommended values to set the RC network for different
input frequency ranges. However, these values are dependent
on the input signal and bandwidth and should be used only as a
starting guide. Note that the values given in Table 9 are for each
R1, R2, C2, and R3 component shown in Figure 50 and Figure 51.
ADA4938-2
0.1µF
33Ω
15pF
15Ω
120Ω
200Ω
Figure 49. Differential Input Configuration Using the ADA4938-2
For baseband applications in which SNR is a key parameter,
differential transformer coupling is the recommended input
configuration. An example is shown in Figure 50. To bias the
analog input, the VCM voltage can be connected to the center
tap of the secondary winding of the transformer.
Table 9. Example RC Network
C2
Frequency
Range
(MHz)
R1
Series
(Ω)
C1
R2
Series
(Ω)
C2
Shunt
(pF)
R3
Shunt
(Ω)
R3
Differential
(pF)
R2
VIN+
R1
ꢀ to 1ꢀꢀ
33
15
8.±
3.9
ꢀ
ꢀ
8.±
49.9
2V p-p
49.9Ω
C1
R1
ADC
VCM
1ꢀꢀ to ±5ꢀ
Open
Open
R2
VIN–
An alternative to using a transformer-coupled input at frequencies
in the second Nyquist zone is to use the AD8376 variable gain
amplifier. An example drive circuit including a band-pass filter
is shown in Figure 52. See the AD8376 data sheet for more
information.
0.1µF
R3
C2
Figure 50. Differential Transformer-Coupled Configuration
C2
R3
0.1µF
0.1µF
0.1µF
R1
R2
R2
VIN+
VIN–
2V p-p
33Ω
33Ω
P
S
S
P
C1
R1
ADC
A
0.1µF
VCM
R3
C2
Figure 51. Differential Double Balun Input Configuration
Rev. D | Page ±1 of 44
AD9644
Data Sheet
1000pF 180nH 220nH
1µH
165Ω
VPOS
15pF
VCM
1nF
AD8376
5.1pF 3.9pF
165Ω
301Ω
1nF
1µH
68nH
AD9644
180nH 220nH
1000pF
NOTES
1. ALL INDUCTORS ARE COILCRAFT 0603CS COMPONENTS
WITH THE EXCEPTION OF THE 1µH CHOKE INDUCTORS (0603LS).
Figure 52. Differential Input Configuration Using the AD8376 (Filter Values Shown Are for a 20 MHz Bandwidth Filter Centered at 140 MHz)
secondary limit clock excursions into the AD9644 to
approximately 0.8 V p-p differential.
VOLTAGE REFERENCE
A stable and accurate voltage reference is built into the AD9644.
The input full scale range can be adjusted through the SPI port by
adjusting Bit 0 through Bit 4 of Register 0x18. These bits can be
used to change the full scale between 1.383 V p-p and 2.087 V p-p
in 0.022 V steps, as shown in Table 17.
This limit helps prevent the large voltage swings of the clock
from feeding through to other portions of the AD9644 while
preserving the fast rise and fall times of the signal that are critical
to a low jitter performance.
CLOCK INPUT CONSIDERATIONS
®
Mini-Circuits
ADC
ADT1-1WT, 1:1Z
For optimum performance, the AD9644 sample clock inputs,
CLK+ and CLK−, should be clocked with a differential signal.
The signal is typically ac-coupled into the CLK+ and CLK− pins by
means of a transformer or a passive component configuration.
These pins are biased internally (see Figure 53) and require no
external bias. If the inputs are floated, the CLK− pin is pulled low
to prevent inadvertent clocking.
0.1µF
50Ω
0.1µF
XFMR
CLOCK
INPUT
CLK+
CLK–
100Ω
0.1µF
SCHOTTKY
DIODES:
HSMS2822
0.1µF
Figure 54. Transformer-Coupled Differential Clock (Up to 200 MHz)
AVDD
ADC
0.9V
1nF
50Ω
1nF
0.1µF
0.1µF
CLOCK
INPUT
CLK+
CLK–
CLK+
CLK–
2pF
2pF
SCHOTTKY
DIODES:
HSMS2822
Figure 55. Balun-Coupled Differential Clock (Up to 640 MHz)
Figure 53. Equivalent Clock Input Circuit
If a low jitter clock source is not available, another option is to
ac couple a differential PECL signal to the sample clock input
pins, as shown in Figure 56. The AD9510/AD9511/AD9512/
AD9513/AD9514/AD9515/AD9516/AD9517/AD9518/AD9520
/AD9522 clock drivers offer excellent jitter performance.
Clock Input Options
The AD9644 has a very flexible clock input structure. Clock input
can be a CMOS, LVDS, LVPECL, or sine wave signal. Regardless
of the type of signal being used, clock source jitter is of the most
concern, as described in the Jitter Considerations section. The
minimum conversion rate of the AD9644 is 40 MSPS. At clock
rates below 40 MSPS, dynamic performance of the AD9644 can
degrade.
0.1µF
0.1µF
CLOCK
INPUT
CLK+
ADC
AD95xx
PECL DRIVER
100Ω
0.1µF
50kΩ
0.1µF
Figure 54 and Figure 55 show two preferred methods for clocking
the AD9644 (at clock rates up to 640 MHz). A low jitter clock
source is converted from a single-ended signal to a differential
signal using either an RF balun or an RF transformer.
CLOCK
INPUT
CLK–
240Ω
240Ω
50kΩ
Figure 56. Differential PECL Sample Clock (Up to 640 MHz)
The RF balun configuration is recommended for clock frequencies
between 125 MHz and 640 MHz, and the RF transformer is
recommended for clock frequencies from 40 MHz to 200 MHz.
The back-to-back Schottky diodes across the transformer/balun
Rev. D | Page ±± of 44
Data Sheet
AD9644
A third option is to ac-couple a differential LVDS signal to the
sample clock input pins, as shown in Figure 57. The AD9510/
AD9511/AD9512/AD9513/AD9514/AD9515/AD9516/AD9517/
AD9518/AD9520/AD9522 clock drivers offer excellent jitter
performance.
Jitter in the rising edge of the input is still of paramount concern
and is not easily reduced by the internal stabilization circuit. The
loop has a time constant associated with it that must be considered
in applications in which the clock rate can change dynamically.
A wait time of 1.5 μs to 5 μs is required after a dynamic clock
frequency increase or decrease before the DCS loop is relocked to
the input signal. During the time period that the loop is not
locked, the DCS loop is bypassed, and internal device timing is
dependent on the duty cycle of the input clock signal. In such
applications, it may be appropriate to disable the duty cycle
stabilizer. In all other applications, enabling the DCS circuit is
recommended to maximize ac performance.
0.1µF
0.1µF
CLOCK
INPUT
CLK+
ADC
AD95xx
LVDS DRIVER
100Ω
0.1µF
0.1µF
50kΩ
CLOCK
INPUT
CLK–
50kΩ
Figure 57. Differential LVDS Sample Clock (Up to 640 MHz)
Jitter Considerations
High speed, high resolution ADCs are sensitive to the quality
of the clock input. For inputs near full scale, the degradation in
SNR from the low frequency SNR (SNRLF) at a given input
frequency (fINPUT) due to jitter (tJRMS) can be calculated by
In some applications, it may be acceptable to drive the sample
clock inputs with a single-ended CMOS signal. In such applica-
tions, the CLK+ pin should be driven directly from a CMOS gate,
and the CLK− pin should be bypassed to ground with a 0.1 ꢀF
capacitor (see Figure 58).
SNRHF = −10 log[(2π × fINPUT × tJRMS)2 + 10 (SNR /10)
]
LF
V
In the equation, the rms aperture jitter represents the clock
input jitter specification. IF undersampling applications are
particularly sensitive to jitter, as illustrated in Figure 59. The
measured curve in Figure 59 was taken using an ADC clock source
with approxi-mately 65 fs of jitter, which combines with the 125 fs
of jitter inherent in the AD9644 to produce the result shown.
75
CC
OPTIONAL
100Ω
0.1µF
0.1µF
1kΩ
1kΩ
AD95xx
CMOS DRIVER
CLOCK
INPUT
CLK+
ADC
1
50Ω
CLK–
0.1µF
1
50Ω RESISTOR IS OPTIONAL.
Figure 58. Single-Ended 1.8 V CMOS Input Clock (Up to 200 MHz)
70
Input Clock Divider
The AD9644 contains an input clock divider with the ability to
divide the input clock by integer values between 1 and 8. For
divide ratios other than 1 the duty cycle stabilizer is automatically
enabled.
0.05ps
0.2ps
0.5ps
1ps
1.5ps
65
60
55
50
MEASURED
The AD9644 clock divider can be synchronized using the external
SYNC input. Bit 1 and Bit 2 of Register 0x3A allow the clock
divider to be resynchronized on every SYNC signal or only on
the first SYNC signal after the register is written. A valid SYNC
causes the clock divider to reset to its initial state. This synchro-
nization feature allows multiple parts to have their clock dividers
aligned to guarantee simultaneous input sampling.
1
10
100
1000
INPUT FREQUENCY (MHz)
Figure 59. SNR vs. Input Frequency and Jitter
The clock input should be treated as an analog signal in cases in
which aperture jitter may affect the dynamic range of the AD9644.
Power supplies for clock drivers should be separated from the
ADC output driver supplies to avoid modulating the clock signal
with digital noise. Low jitter, crystal-controlled oscillators make
the best clock sources. If the clock is generated from another type
of source (by gating, dividing, or another method), it should be
retimed by the original clock at the last step.
Clock Duty Cycle
Typical high speed ADCs use both clock edges to generate
a variety of internal timing signals and, as a result, may be
sensitive to clock duty cycle. The AD9644 requires a tight
tolerance on the clock duty cycle to maintain dynamic
performance characteristics.
The AD9644 contains a duty cycle stabilizer (DCS) that retimes
the nonsampling (falling) edge, providing an internal clock signal
with a nominal 50% duty cycle. This allows the user to provide
a wide range of clock input duty cycles without affecting the
perfor-mance of the AD9644. Noise and distortion
performance are nearly flat for a wide range of duty cycles with
the DCS enabled.
Refer to the AN-501 Application Note and the AN-756
Application Note (visit www.analog.com) for more information
about jitter performance as it relates to ADCs.
Rev. D | Page ±3 of 44
AD9644
Data Sheet
By asserting PDWN (either through the SPI port or by asserting
the PDWN pin high), the AD9644 is placed in power-down mode.
In this state, the ADC typically dissipates 15 mW. During power-
down, the output drivers are placed in a high impedance state.
Asserting the PDWN pin low returns the AD9644 to its normal
operating mode.
CHANNEL/CHIP SYNCHRONIZATION
The AD9644 has a SYNC input that offers the user flexible
synchronization options for synchronizing the clock divider.
The clock divider sync feature is useful for guaranteeing synchro-
nized sample clocks across multiple ADCs. The input clock
divider can be enabled to synchronize on a single occurrence of
the SYNC signal or on every occurrence.
Low power dissipation in power-down mode is achieved by
shutting down the reference, reference buffer, biasing networks,
clock, and JESD204A outputs . Internal capacitors are discharged
when entering power-down mode and then must be recharged
when returning to normal operation.
The SYNC input is internally synchronized to the sample clock;
however, to ensure that there is no timing uncertainty between
multiple parts, the SYNC input signal should be externally syn-
chronized to the input clock signal, meeting the setup and hold
times shown in Table 5. The SYNC input should be driven
using a single-ended CMOS-type signal.
When using the SPI port interface, the user can place the ADC
in power-down mode or standby mode. Standby mode allows
the user to keep the internal reference circuitry powered and
the JESD204A outputs running when faster wake-up times are
required.
POWER DISSIPATION AND STANDBY MODE
As shown in Figure 60 and Figure 61, the power dissipated by
the AD9644 varies with its sample rate (AD9644-80 shown).
DIGITAL OUTPUTS
JESD204A Transmit Top Level Description
The data in Figure 60 and Figure 61 was taken in JESD204A
serial output mode, using the same operating conditions as those
used for the Typical Performance Characteristics.
The AD9644 digital output complies with the JEDEC Standard
No. 204A (JESD204A), which describes a serial interface for
data converters. JESD204A uses 8B/10B encoding as well as
optional scrambling. K28.5 and K28.7 comma symbols are used
for frame synchronization and the K28.3 control symbol is used
for lane synchronization. The receiver is required to lock onto
the serial data stream and recover the clock with the use of a
PLL. For details on the output interface, users are encouraged
to refer to the JESD204A standard.
0.5
0.4
0.3
0.2
0.1
0
0.25
0.20
0.15
0.10
0.05
0
TOTAL POWER
IAVDD
The JESD204A transmit block is used to multiplex data from
the two analog-to-digital converters onto two independent
JESD204A Links. Each JESD204A Link is considered a separate
instance of the JESD204A specification, has an independent
DSYNC signal, and contains one or more lanes. Note that the
JESD204 specification only allows one lane per link, while the
JESD204A specification adds multilane support through an
alignment procedure.
IDRVDD
40
50
60
70
80
ENCODE FREQUENCY (MSPS)
Figure 60. AD9644-80 Power and Current vs. Encode Frequency with fIN
10.1 MHz
=
Each JESD204A Link is described according to the following
nomenclature:
0.60
0.50
0.40
0.30
0.20
0.10
0
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
TOTAL POWER
S = samples transmitted/single converter/frame cycle
M = number of converters/converter device (link)
L = number of lanes/converter device (link)
N = converter resolution
N’ = total number of bits per sample
CF = number of control words/frame clock
cycle/converter device (link)
I
AVDD
I
DRVDD
CS = number of control bits/conversion sample
K = number of frames per multiframe
HD = high density mode
F = octets/frame
C = control bit (overrange, overflow, underflow)
T = tail bit
80
90
100
110
120
130
140
150
ENCODE FREQUENCY (MSPS)
Figure 61. AD9644-155 Power and Current vs. Encode Frequency
with fIN = 10.1 MHz
SCR = scrambler enable/disable
FCHK = checksum
Rev. D | Page ±4 of 44
Data Sheet
AD9644
Figure 62 shows a simplified block diagram of the AD9644
JESD204A links. The two links each have a primary and a
secondary converter input and lane output. By default, the
primary Input 0 of Link A is ADC Converter A and its primary
lane Output 0 is sent on output Lane A. The primary Input 0 of
Link B is ADC Converter B and its primary lane Output 0 is
sent on output Lane B. Muxes throughout the design are used
to enable secondary inputs/outputs and swap lane outputs for
other configurations. The JESD204A block for AD9644 is
designed to support the configurations described in Table 10
via a quick configuration register at Address 0x5E accessible via
the SPI bus.
AD9644, the 14-bit converter word is broken into two octets.
Bit 13 through Bit 6 are in the first octet. The second octet
contains Bit 5 through Bit 0 and two tail bits. The MSB of the tail
bits can also be used to indicate an out-of-range condition. The
tail bits are configured using the JESD204A link control
Register 1, Address 0x60, Bit 6.
The two resulting octets are optionally scrambled and encoded
into their corresponding 10-bit code. The scrambling function
is controlled by the JESD204A scrambling and lane configuration
register, Address 0x06E, Bit 7. Figure 63 shows how the 14-bit
data is taken from the ADC, the tail bits are added, the two
octets are scrambled, and how the octets are encoded into two
10-bit symbols. Figure 63 illustrates the default data format.
In addition to the default mode, the user can program the AD9644
to output both ADC channels on a single lane (F = 4). This mode
allows use of a single high speed data lane, which simplifies board
layout and connector requirements. In Figure 64 the ADC A
output is represented by Word 0 and the ADC B output by Word
1. The third output mode utilizes a single link to support both
channels. In single link mode, the DSYNCA pin is used to support
both outputs. This mode is useful for optimal alignment between
the output channels.
The scrambler uses a self-synchronizing polynomial-based
algorithm defined by the equation 1 + x14 + x15. The descrambler
in the receiver should be a self-synchronizing version of the
scrambler polynomial. Figure 65 shows the corresponding
receiver data path.
Refer to JEDEC Standard No. 204A-April 2008, Section 5.1, for
complete transport layer and data format details and Section
5.2 for a complete explanation of scrambling and descrambling.
The 8B/10B encoding works by taking eight bits of data (an octet)
and encoding them into a 10-bit symbol. By default in the
AD9644
DUAL ADC
LINK A
~SYNC
CONVERTER A
INPUT
CONVERTER A
SAMPLE
LANE 0
LANE 1
LANE 1
LANE 0
PRIMARY
PRIMARY
LANE
A
B
LANE A
CONVERTER A
CONVERTER
INPUT [0]
OUTPUT [0]
JESD204A LINK A
(M = 0, 1, 2; L = 0, 1, 2)
SECONDARY
CONVERTER
INPUT [1]
SECONDARY
LANE
OUTPUT [1]
LANE
MUX
(SPI
REGISTER
0x5F)
A
B
SECONDARY
CONVERTER
INPUT [1]
SECONDARY
LANE
OUTPUT [1]
JESD204A LINK B
(M = 0, 1, 2; L = 0, 1, 2)
CONVERTER B
INPUT
LANE B
PRIMARY
CONVERTER
INPUT [0]
PRIMARY
LANE
OUTPUT [0]
CONVERTER B
CONVERTER B
SAMPLE
LINK B
~SYNC
Figure 62. AD9644 Transmit Link Simplified Block Diagram
Rev. D | Page ±5 of 44
AD9644
Data Sheet
Table 10. AD9644 JESD204A Typical Configurations
AD9644 Configuration
JESK204A Link A Settings
M = 1; L = 1; S = 1; F = ±
N’ = 16; CF = ꢀ
JESD204A Link B Settings
M = 1; L = 1; S = 1; F = ±
N’ = 16; CF = ꢀ
Comments
Maximum sample rate = 8ꢀ MSPS or 155 MSPS
Two Converters
Two JESD±ꢀ4A Links
One Lane Per Link
CS = ꢀ, 1, ±; K = N/A
SCR = ꢀ, 1; HD = ꢀ
M = ±; L = ±; S = 1; F = ±
N’ = 16
CS = ꢀ, 1, ±; K = N/A
SCR = ꢀ, 1; HD = ꢀ
Disabled
Maximum sample rate = 8ꢀ MSPS or 155 MSPS
Required for applications needing two aligned
samples (I/Q applications)
Two Converters
One JESD±ꢀ4A Link
Two Lanes Per Link
CF = ꢀ; CS = ꢀ, 1, ±
K = 16; SCR = ꢀ, 1;
HD = ꢀ
M = ±; L = 1; S = 1; F = 4
N’ = 16
Disabled
Maximum sample rate = 8ꢀ MSPS
Two Converters
One JESD±ꢀ4A Link
One Lane Per Link
CF = ꢀ; CS = ꢀ, 1, ±
K = 8; SCR = ꢀ, 1; HD = ꢀ
DATA
FROM
ADC
FRAME
ASSEMBLER
(ADD TAIL BITS)
OPTIONAL
8B/10B
ENCODER
TO
RECEIVER
SCRAMBLER
14
15
1 + x + x
Figure 63. AD9644 ADC Output Data Path
WORD 0[13:6]
SYMBOL 0[9:0]
FRAME 0
FRAME 1
WORD 0[5:0],TAIL BITS[1:0]
WORD 1[13:6]
SYMBOL 1[9:0]
SYMBOL 2[9:0]
SYMBOL 3[9:0]
TIME
WORD 1[5:0], TAIL BITS[1:0]
Figure 64. AD9644 14-Bit Data Transmission with Tail Bits
OPTIONAL
8B/10B
DECODER
FRAME
ALIGNMENT
DATA
OUT
FROM
TRANSMITTER
DESCRAMBLER
14 15
1 + x + x
Figure 65. Required Receiver Data Path
Initial Frame Synchronization
The DSYNC input can be driven either from a differential
LVDS source or by using a single-ended CMOS driver circuit.
The DSYNC input default to LVDS mode but can be set to
CMOS mode by setting Bit 4 in SPI Address 0x61. If it is driven
differentially from an LVDS source, then an external 100 Ω
termination resistor should be provided. If the DSYNC input is
driven single-ended then the CMOS signal should be connected
to the DSYNC+ signal and the DSYNC− signal should be left
disconnected.
The serial interface must synchronize to the frame boundaries
before data can be properly decoded. The JESD204A standard
has a synchronization routine to identify the frame boundary.
When the DSYNC pin is taken low for at least two clock cycles,
the AD9644 enters the code group synchronization mode. The
AD9644 transmits the K28.5 comma symbol until the receiver
achieves synchronization. The receiver should then deassert the
sync signal (take DSYNC high) and the AD9644 begins the initial
lane alignment sequence (when enabled through Bits[3:2] of
Address 0x60) and subsequently begins transmitting sample
data. The first non-K28.5 symbol corresponds to the first octet
in a frame.
Rev. D | Page ±6 of 44
Data Sheet
AD9644
Table 11. AD9644 JESD204A Frame Alignment Monitoring and Correction Replacement Characters
Last Octet in
Multiframe
Scrambling Lane Synchronization Character to be Replaced
Replacement Character
K±8.7 (ꢀxFC)
K±8.3 (ꢀx7C)
Off
Off
Off
On
On
On
On
On
Off
On
On
Off
Last octet in frame repeated from previous frame
Last octet in frame repeated from previous frame
Last octet in frame repeated from previous frame
Last octet in frame equals D±8.7 (ꢀxFC)
Last octet in frame equals D±8.3 (ꢀx7C)
Last octet in frame equals D±8.7 (ꢀx7C)
No
Yes
Not applicable K±8.7 (ꢀxFC)
No
Yes
K±8.7 (ꢀxFC)
K±8.3 (ꢀx7C)
Not applicable K±8.7 (ꢀxFC)
common mode of the digital output automatically biases itself
to half the supply of the receiver (that is, the common-mode
voltage is 0.9 V for a receiver supply of 1.8 V) if dc-coupled
connecting is used (see Figure 67). For receiver logic that is not
within the bounds of the DRVDD supply, an ac-coupled
connection should be used. Simply place a 0.1 μF capacitor on
each output pin and derive a 100 Ω differential termination
close to the receiver side.
Frame and Lane Alignment Monitoring and Correction
Frame alignment monitoring and correction is part of the
JESD204A specification. The 14-bit word requires two octets to
transmit all the data. The two octets (MSB and LSB), where
F = 2, make up a frame. During normal operating conditions
frame alignment is monitored via alignment characters, which
are inserted under certain conditions at the end of a frame.
Table 11 summarizes the conditions for character insertion
along with the expected characters under the various operation
modes. If lane synchronization is enabled, the replacement
character value depends on whether the octet is at the end of a
frame or at the end of a multiframe.
If there is no far-end receiver termination or if there is poor
differential trace routing, timing errors may result. To avoid
such timing errors, it is recommended that the trace length be
less than six inches and that the differential output traces be
close together and at equal lengths.
Based on the operating mode, the receiver can ensure that it is
still synchronized to the frame boundary by correctly receiving
the replacement characters.
V
RXCM
100Ω
DIFFERENTIAL
DRVDD
Digital Outputs and Timing
TRACE PAIR
0.1µF
0.1µF
DOUT+x
DOUT–x
The AD9644 has differential digital outputs that power up
by default. The driver current is derived on chip and sets the
output current at each output equal to a nominal 4 mA. Each
output presents a 100 Ω dynamic internal termination to
reduce unwanted reflections.
RECEIVER
= Rx V
100Ω
OR
V
OUTPUT SWING = 400mV p-p
CM
CM
A 100 Ω differential termination resistor should be placed at
each receiver input to result in a nominal 400 mV peak-to-peak
swing at the receiver (see Figure 66). Alternatively, single-
ended 50 Ω termina-tion can be used. When single-ended
termination is used, the termination voltage should be
DRVDD/2; otherwise, ac coupling capacitors can be used to
terminate to any single-ended voltage.
Figure 66. AC-Coupled Digital Output Termination Example
100Ω
DIFFERENTIAL
TRACE PAIR
DRVDD
DOUT+x
RECEIVER
100Ω
DOUT–x
V
= DRVDD/2
OUTPUT SWING = 400mV p-p
The AD9644 digital outputs can interface with custom ASICs
and FPGA receivers, providing superior switching performance
in noisy environments. Single point-to-point network topologies
are recommended with a single differential 100 Ω termination
resistor placed as close to the receiver logic as possible. The
CM
Figure 67. DC-Coupled Digital Output Termination Example
Rev. D | Page ±7 of 44
AD9644
Data Sheet
WIDTH@BER1: BATHTUB
HEIGHT1: EYE DIAGRAM
PERIOD1: HISTOGRAM
0
10
1
4
3
25,000
20,000
15,000
10,000
5000
–
+
+
–2
–4
–6
–8
10
10
10
10
400
200
0
–200
–400
–10
–12
–14
10
10
10
0.781
EYE: TRANSITION BITS
OFFSET: –0.004
ULS: 8000; 639999, TOTAL: 8000; 639999
0
–600 –400 –200
0
200 400 600
610 615 620 625 630 635
TIME (ps)
–0.5
0
0.5
TIME (ps)
ULS
Figure 68. AD9644-80 Digital Outputs Data Eye, Histogram and Bathtub, External 100 Ω Terminations
WIDTH@BER1: BATHTUB
HEIGHT1: EYE DIAGRAM
PERIOD1: HISTOGRAM
0
10
1
4
3
500
400
300
50,000
45,000
40,000
–
–
–
–2
–4
–6
–8
10
10
10
10
200
100
0
35,000
30,000
25,000
20,000
15,000
10,000
–100
–200
–300
–10
–12
–14
10
10
10
0.742
–400
–500
EYE: TRANSITION BITS
OFFSET: –0.004
ULS: 8000; 124,0001, TOTAL: 8000; 124,0001
5000
0
–300 –200 –100
0
100 200 300
305 310 315 320 325 330 335
TIME (ps)
–0.5
0
0.5
TIME (ps)
ULS
Figure 69. AD9644-155 Digital Outputs Data Eye, Histogram and Bathtub, External 100 Ω Terminations
Figure 68 and Figure 69 shows an example of the digital output
(default) data eye and a time interval error (TIE) jitter histogram.
Table 12. Digital Output Coding
Digital Output
Twos Complement
([D13:D0])
(VIN+ ) − (VIN− ),
Input Span = 1.75 V p-p (V)
Additional SPI options allow the user to further increase the
output driver voltage swing of all four outputs to drive longer
trace lengths (see Address 0x15 in Table 17). Even though this
produces sharper rise and fall times on the data edges and is
less prone to bit errors, the power dissipation of the DRVDD
supply increases when this option is used. See the Memory Map
section for more details.
Code
8191
ꢀ
+ꢀ.875
ꢀ.ꢀꢀ
ꢀ1 1111 1111 1111
ꢀꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ
11 1111 1111 1111
1ꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ
−1
−ꢀ.ꢀꢀꢀ1ꢀ7
−819± −ꢀ.875
The lowest typical clock rate is 40 MSPS. For clock rates slower
than 60 MSPS, the user should set Bit 3 to 0 in the serial control
register (Address 0x21 in Table 17). This option sets the PLL
loop bandwidth to use clock rates between 40 MSPS and
60 MSPS.
The format of the output data is twos complement by default.
Table 12 provides an example of this output coding format.
To change the output data format to offset binary or gray code,
see the Memory Map section (Address 0x14 in Table 17).
Setting Bit 2 in the output mode register (Address 0x14) allows
the user to invert the digital samples from their nominal state.
As shown in Figure 64, the MSB is transmitted first in the data
output serial stream.
Rev. D | Page ±8 of 44
Data Sheet
AD9644
BUILT-IN SELF-TEST (BIST) AND OUTPUT TEST
The AD9644 includes built-in test features designed to enable
verification of the integrity of each channel as well as facilitate
board level debugging. A BIST (built-in self-test) feature is
included that verifies the integrity of the digital datapath of the
AD9644. Various output test options are also provided to place
predictable values on the outputs of the AD9644.
For more information, see the AN-877 Application Note,
Interfacing to High Speed ADCs via SPI.
There are nine digital output test pattern options available that
can be initiated through the SPI (see Table 14 for the output bit
sequencing options). This feature is useful when validating
receiver capture and timing. Some test patterns have two serial
sequential words and can be alternated in various ways,
BUILT-IN SELF-TEST (BIST)
depending on the test pattern selected. Note that some patterns
do not adhere to the data format select option. In addition,
custom user-defined test patterns can be assigned in the user
pattern registers (Address 0x19 through Address 0x20).
The BIST is a thorough test of the digital portion of the selected
AD9644 signal path. When enabled, the test runs from an internal
pseudorandom noise (PN) source through the digital datapath
starting at the ADC block output. The BIST sequence runs for
512 cycles and stops. The BIST signature value for Channel A
and/or Channel B is placed in Register 0x24 and Register 0x25.
The outputs are not disconnected during this test, so the PN
sequence can be observed as it runs. The PN sequence can be
continued from its last value or reset from the beginning, based
on the value programmed in Register 0x0E, Bit 2. The BIST
signature result varies based on the channel configuration.
The PN sequence short pattern produces a pseudorandom bit
sequence that repeats itself every 29 − 1 (511) bits. A description
of the PN sequence short and how it is generated can be found
in Section 5.1 of the ITU-T O.150 (05/96) recommendation.
The only difference is that the starting value must be a specific
value instead of all 1s (see Table 13 for the initial values).
The PN sequence long pattern produces a pseudorandom bit
sequence that repeats itself every 223 − 1 (8,388,607) bits. A
description of the PN sequence long and how it is generated
can be found in Section 5.6 of the ITU-T O.150 (05/96)
standard. The only differences are that the starting value must be
a specific value instead of all 1s (see Table 13 for the initial
values) and that the AD9644 inverts the bit stream with relation
to the ITU-T standard.
OUTPUT TEST MODES
Digital Test patterns can be inserted at various points along the
signal path within the AD9644 as shown in Figure 70. The
ability to inject these signals at several locations facilitates
debugging of the JESD204A serial communication link.
The Register 0x0D allows test signals generated at the output of
the ADC core to be fed directly into the input of the serial Link.
The output test options available from Register 0x0D are shown
in Table 17. When an output test mode is enabled, the analog
section of the ADC is disconnected from the digital back end
blocks and the test pattern is run through the output formatting
block. Some of the test patterns are subject to output formatting,
and some are not. The seed value for the PN sequence tests can
be forced if the PN reset bits are used to hold the generator in reset
mode by setting Bit 4 or Bit 5 of Register 0x0D. These tests can
be performed with or without an analog signal (if present, the
analog signal is ignored), but they do require an encode clock.
Table 13. PN Sequence
Initial
Value
First Three Output Samples
(MSB First)
Sequence
PN Sequence Short
PN Sequence Long
ꢀxꢀꢀ9±
ꢀx3AFF
ꢀx1±5B, ꢀx3C9A, ꢀx±66ꢀ
ꢀx3FD7, ꢀxꢀꢀꢀ±, ꢀx36Eꢀ
The Register 0x62 allows patterns similar to those described in
Table 14 to be input at different points along the data path.
This allows the user to provide predictable output data on the
serial link without it having been manipulated by the internal
formatting logic. Refer to Table 17 for additional information
on the test modes available in Register 0x62.
Rev. D | Page ±9 of 44
AD9644
Data Sheet
Table 14. Flexible Output Test Modes from SPI Register 0x0D
Digital Output Word 1
(Default Twos Complement
Format)
Digital Output Word 2
(Default Twos Complement
Format)
Output Test Mode
Bit Sequence
Subject to Data
Format Select
Pattern Name
ꢀꢀꢀꢀ
ꢀꢀꢀ1
ꢀꢀ1ꢀ
ꢀꢀ11
ꢀ1ꢀꢀ
ꢀ1ꢀ1
ꢀ11ꢀ
ꢀ111
1ꢀꢀꢀ
Off (default)
Midscale short
Not applicable
Not applicable
Same
Same
Yes
Yes
Yes
Yes
No
Yes
Yes
No
ꢀꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ
ꢀ1 1111 1111 1111
1ꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ
1ꢀ 1ꢀ1ꢀ 1ꢀ1ꢀ 1ꢀ1ꢀ
Not applicable
Not applicable
1111 1111 1111
User data from Register ꢀx19 to
Register ꢀx±ꢀ
+Full-scale short
−Full-scale short
Checkerboard
PN sequence long
PN sequence short
One-/zero-word toggle
User test mode
Same
ꢀ1 ꢀ1ꢀ1 ꢀ1ꢀ1 ꢀ1ꢀ1
Not applicable
Not applicable
ꢀꢀꢀꢀ ꢀꢀꢀꢀ ꢀꢀꢀꢀ
User data from Register ꢀx19 to
Register ꢀx±ꢀ
Yes
1ꢀꢀ1 to 111ꢀ
1111
Not used
Ramp output
Not applicable
N
Not applicable
N + 1
No
JESD204A TEST PATTERNS
10-BIT
SPI REGISTER 0x62 BITS 5:4 =
01 AND BITS 2:0 ≠ 000
ADC TEST PATTERNS
14-BIT
SPI REGISTER 0x0D
BITS 3:0 ≠ 0000
JESD204A TEST PATTERNS
16-BIT
SPI REGISTER 0x62 BITS 5:4 =
00 AND BITS 2:0 ≠ 000
SERALIZER
OUTPUT
FRAME
CONSTRUCTION
SCRAMBLER
(OPTIONAL)
8-BIT/10-BIT
ENCODER
JESD204A
SAMPLE
CONSTRUCTION
ADC CORE
FRAMER
TAIL BITS
Figure 70. Block Diagram Showing Digital Test Modes
Rev. D | Page 3ꢀ of 44
Data Sheet
AD9644
SERIAL PORT INTERFACE (SPI)
The AD9644 serial port interface (SPI) allows the user to configure
the converter for specific functions or operations through a
structured register space provided inside the ADC. The SPI
gives the user added flexibility and customization, depending on
the application. Addresses are accessed via the serial port and can
be written to or read from via the port. Memory is organized into
bytes that can be further divided into fields, which are documented
in the Memory Map section. For detailed operational
information, see the AN-877 Application Note, Interfacing to
High Speed ADCs via SPI.
The falling edge of the CSB, in conjunction with the rising edge
of the SCLK, determines the start of the framing. An example
of the serial timing and its definitions can be found in Figure 71
and Table 5.
Other modes involving the CSB are available. The CSB can be
held low indefinitely, which permanently enables the device;
this is called streaming. The CSB can stall high between bytes to
allow for additional external timing. When CSB is tied high,
SPI functions are placed in high impedance mode.
During an instruction phase, a 16-bit instruction is transmitted.
Data follows the instruction phase, and its length is determined
by the W0 and W1 bits.
CONFIGURATION USING THE SPI
Three pins define the SPI of this ADC: the SCLK pin, the SDIO
pin, and the CSB pin (see Table 15). The SCLK (a serial clock)
is used to synchronize the read and write data presented from
and to the ADC. The SDIO (serial data input/output) is a dual-
purpose pin that allows data to be sent to and read from the
internal ADC memory map registers. The CSB (chip select bar)
is an active-low control that enables or disables the read and
write cycles.
In addition to word length, the instruction phase determines
whether the serial frame is a read or write operation, allowing
the serial port to be used both to program the chip and to read
the contents of the on-chip memory. The first bit of the first byte in
a multibyte serial data transfer frame indicates whether a read
command or a write command is issued. If the instruction is a
readback operation, performing a readback causes the serial
data input/output (SDIO) pin to change direction from an input
to an output at the appropriate point in the serial frame.
Table 15. Serial Port Interface Pins
Pin
Function
SCLK Serial Clock. The serial shift clock input is used to
synchronize serial interface reads and writes.
SDIO Serial Data Input/Output. A dual-purpose pin that
typically serves as an input or an output, depending on
the instruction being sent and the relative position in the
timing frame.
All data is composed of 8-bit words. Data can be sent in MSB-
first mode or in LSB-first mode. MSB first is the default on
power-up and can be changed via the SPI port configuration
register. For more information about this and other features,
see the AN-877 Application Note, Interfacing to High Speed
ADCs via SPI.
CSB
Chip Select Bar. An active-low control that gates the read
and write cycles.
tHIGH
tDS
tCLK
tH
tS
tDH
tLOW
CSB
SCLK DON’T CARE
SDIO DON’T CARE
DON’T CARE
R/W
W1
W0
A12
A11
A10
A9
A8
A7
D5
D4
D3
D2
D1
D0
DON’T CARE
Figure 71. Serial Port Interface Timing Diagram
Rev. D | Page 31 of 44
AD9644
Data Sheet
HARDWARE INTERFACE
SPI ACCESSIBLE FEATURES
The pins described in Table 15 comprise the physical interface
between the user programming device and the serial port of the
AD9644. The SCLK pin and the CSB pin function as inputs
when using the SPI interface. The SDIO pin is bidirectional,
functioning as an input during write phases and as an output
during readback.
Table 16 provides a brief description of the general features that
are accessible via the SPI. These features are described in detail
in the AN-877 Application Note, Interfacing to High Speed ADCs
via SPI. The AD9644 part-specific features are described in detail
in the Memory Map Register Descriptions section.
Table 16. Features Accessible Using the SPI
The SPI interface is flexible enough to be controlled by either
FPGAs or microcontrollers. One method for SPI configuration
is described in detail in the AN-812 Application Note, Micro-
controller-Based Serial Port Interface (SPI) Boot Circuit.
Feature Name
Description
Mode
Allows the user to set either power-down mode
or standby mode
Clock
Allows the user to access the DCS, set the
clock divider, set the clock divider phase, and
enable the sync
The SPI port should not be active during periods when the full
dynamic performance of the converter is required. Because the
SCLK signal, the CSB signal, and the SDIO signal are typically
asynchronous to the ADC clock, noise from these signals can
degrade converter performance. If the on-board SPI bus is used for
other devices, it may be necessary to provide buffers between
this bus and the AD9644 to prevent these signals from transi-
tioning at the converter inputs during critical sampling periods.
Offset
Allows the user to digitally adjust the
converter offset
Test I/O
Full Scale
JESD±ꢀ4A
Allows the user to set test modes to have
known data on output bits
Allows the user to set the input full scale
voltage
Allows user to configure the JESD±ꢀ4A output
Rev. D | Page 3± of 44
Data Sheet
AD9644
MEMORY MAP
Logic Levels
READING THE MEMORY MAP REGISTER TABLE
An explanation of logic level terminology follows:
Each row in the memory map register table has eight bit locations.
The memory map is roughly divided into four sections: the chip
configuration registers (Address 0x00 to Address 0x02); the
channel index and transfer registers (Address 0x05 and
Address 0xFF); the ADC functions registers, including setup,
control, and test (Address 0x08 to Address 0x3A); and the
JESD204A configuration registers (Address 0x5E to Address 0x79).
“Bit is set” is synonymous with “bit is set to Logic 1” or
“writing Logic 1 for the bit.”
“Clear a bit” is synonymous with “bit is set to Logic 0” or
“writing Logic 0 for the bit.”
Transfer Register Map
Address 0x08 through Address 0x79 are shadowed. Writes to
these addresses do not affect part operation until a transfer
command is issued by writing 0x01 to Address 0xFF, setting the
transfer bit. This allows these registers to be updated internally
and simultaneously when the transfer bit is set. The internal
update takes place when the transfer bit is set, and the bit
autoclears.
The memory map register table (see Table 17) lists the default
hexadecimal value for each hexadecimal address shown. The
column with the heading Bit 7 (MSB) is the start of the default
hexadecimal value given. For example, Address 0x18, the input
span select register, has a hexadecimal default value of 0x00. This
means that Bit 0 through Bit 4 = 0, and the remaining bits are 0s.
This setting is the default reference selection setting. The default
value uses a 1.75 V p-p reference. For more information on this
function and others, see the AN-877 Application Note, Interfacing
to High Speed ADCs via SPI. This application note details the
functions con-trolled by Register 0x00 to Register 0xFF.
Channel-Specific Registers
Some channel setup functions, such as the channel output
mode, can be programmed differently for each ADC or link
channel. In these cases, channel address locations are internally
duplicated for each channel. These registers and bits are
designated in Table 17 as local. These local registers and bits
can be accessed by setting the appropriate Channel A/Link A or
Channel B/Link B bits in Register 0x05.
Open Locations
All address and bit locations that are not included in Table 17
are not currently supported for this device. Unused bits of a
valid address location should be written with 0s. Writing to these
locations is required only when part of an address location is open
(for example, Address 0x18). If the entire address location is
open (for example, Address 0x13), this address location should not
be written.
If both bits are set in register 0x05, the subsequent write affects
the registers of both channels/links. In a SPI read cycle, only
Channel A/Link A or Channel B/Link B should be set to read
one of the two registers. If both bits are set during an SPI read
cycle, the part returns the value for Channel A/Link A. Registers
and bits designated as global in Table 17 affect the entire part or
the channel features for which independent settings are not
allowed between channels. The settings in Register 0x05 do not
affect the global registers and bits.
Default Values
After the AD9644 is reset, critical registers are loaded with
default values. The default values for the registers are given in
the memory map register table, Table 17.
Rev. D | Page 33 of 44
AD9644
Data Sheet
MEMORY MAP REGISTER TABLE
All address and bit locations that are not included in Table 17 are not currently supported for this device.
Table 17. Memory Map Registers
Default
Addr
(Hex)
Register
Name
Bit 7
(MSB)
Bit 0
(LSB)
Value
(Hex)
Default/
Comments
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Chip Configuration Registers
ꢀxꢀꢀ
SPI port
configuration
(global)1
ꢀ
LSB first
Soft reset
1
1
Soft reset
LSB first
ꢀ
ꢀx18
Nibbles are
mirrored so
that LSB-first
or MSB-first
mode is set
correctly,
regardless of
shift mode.
To control
this register,
all channel
index bits in
Register
ꢀxꢀ5 must
be set.
ꢀxꢀ1
ꢀxꢀ±
Chip ID
(global)
8-bit chip ID[7:ꢀ]
(AD9644 = ꢀx7E)
(default)
ꢀx7E
Read only
Chip grade
(global)
Open
Open
Open
Speed grade ID
Open
Open
Open
Open
Open
Speed grade
ID
differentiates
devices;
ꢀꢀ = 8ꢀ MSPS
1ꢀ = 155 MSPS
read only
Channel Index and Transfer Registers
ꢀxꢀ5
Channel index Open
(global)
Open
Open
Open
ADC B and ADC A and
Link B
(default)
ꢀxꢀ3
Bits set to
determine
which
Link A
(default)
device on
the chip
receives
next write
command;
local
registers
only
ꢀxFF
Transfer
(global)
Open
Open
Open
Open
Open
Open
Open
Open
Open
Transfer
ꢀxꢀꢀ
Synchro-
nously
transfers
data from
master shift
register to
slave
ADC Functions
ꢀxꢀ8
Power modes
(local)
Open
Open
Open
Open
External power-
down pin
function (local)
ꢀ = power-
down
Open
Internal power-down mode
(local)
ꢀꢀ = normal operation
ꢀ1 = full power-down
1ꢀ = standby
ꢀxꢀꢀ
ꢀxꢀ1
Determines
various
generic
modes of
chip
operation
1 = standby
11 = reserved
ꢀxꢀ9
Global clock
(global)
Open
Open
Open
Open
Open
Open
Open
Open
Open
Duty cycle
stabilizer
(default)
ꢀxꢀA
ꢀxꢀB
PLL status
(global)
PLL
Locked
Open
Open
Open
Open
ꢀxꢀꢀ
ꢀxꢀꢀ
Read Only
Clock divide
(global)
Open
Input clock divider phase adjust
ꢀꢀꢀ = no delay
Clock divide ratio
ꢀꢀꢀ = divide by 1
ꢀꢀ1 = divide by ±
ꢀ1ꢀ = divide by 3
ꢀ11 = divide by 4
1ꢀꢀ = divide by 5
1ꢀ1 = divide by 6
11ꢀ = divide by 7
111 = divide by 8
Clock divide
values other
than ꢀꢀꢀ
automatically
causes duty
cycle
stabilizer to
become
active
ꢀꢀ1 = 1 input clock cycle
ꢀ1ꢀ = ± input clock cycles
ꢀ11 = 3 input clock cycles
1ꢀꢀ = 4 input clock cycles
1ꢀ1 = 5 input clock cycles
11ꢀ = 6 input clock cycles
111 = 7 input clock cycles
Rev. D | Page 34 of 44
Data Sheet
AD9644
Default
Value
(Hex)
Addr
(Hex)
Register
Name
Bit 7
(MSB)
Bit 0
(LSB)
Default/
Comments
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
ꢀxꢀD
Test mode
(local)
User test
mode
control
Open
Reset PN long
generator
Reset
PN
short
generat
or
Output test mode
ꢀꢀꢀꢀ = off (default)
ꢀꢀꢀ1 = midscale short
ꢀꢀ1ꢀ = positive FS
ꢀꢀ11 = negative FS
ꢀxꢀꢀ
When this
register is
set, test data
is used in
place of
normal ADC
data
ꢀ =
continuo
us/repeat
pattern
1 = single
pattern
ꢀ1ꢀꢀ = alternating checkerboard
ꢀ1ꢀ1 = PN long sequence
ꢀ11ꢀ = PN short sequence
ꢀ111 = one/zero word toggle
1ꢀꢀꢀ = user test mode
1ꢀꢀ1 to 111ꢀ = unused
1111 = ramp output
ꢀxꢀE
ꢀx1ꢀ
ꢀx14
BIST enable
(global)
Open
Open
Open
Open
Open
Open
Open
Open
Open
Open
Reset BIST
sequence
Open
BIST enable
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀ1
Offset adjust
(local)
Offset adjust in LSBs from +31 to −3±
(twos complement format)
Output mode
Output
disable
(local)
Open
Output
invert
(local)
Output format
ꢀꢀ = offset binary
ꢀ1 = twos complement
(default)
Configures
outputs and
the format
of the data
1ꢀ = gray code
11 = offset binary
(local)
ꢀx15
ꢀx18
Output adjust
(global)
Open
Open
Open
Open
Open
Open
Open
Open
Open
Output drive level
adjust
11 = 3±ꢀ mV
ꢀꢀ = 4ꢀꢀ mV
1ꢀ = 44ꢀ mV
ꢀ1 = 5ꢀꢀ mV
ꢀxꢀꢀ
ꢀxꢀꢀ
Input span
select
(global)
Full-scale input voltage selection
ꢀ1111 = ±.ꢀ87 V p-p
…
Full-scale
input
adjustment
in ꢀ.ꢀ±± V
steps
ꢀꢀꢀꢀ1 = 1.77± V p-p
ꢀꢀꢀꢀꢀ = 1.75 V p-p (default)
11111 = 1.7±7 V p-p
…
1ꢀꢀꢀꢀ = 1.383 V p-p
ꢀx19
ꢀx1A
ꢀx1B
ꢀx1C
ꢀx1D
ꢀx1E
ꢀx1F
ꢀx±ꢀ
ꢀx±1
User Test
Pattern 1 LSB
(global)
User Test Pattern 1 [7:ꢀ]
User Test Pattern 1 [15:8]
User Test Pattern ± [7:ꢀ]
User Test Pattern ± [15:8]
User Test Pattern 3 [7:ꢀ]
User Test Pattern 3 [15:8]
User Test Pattern 4 [7:ꢀ]
User Test Pattern 4 [15:8]
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
User Test
Pattern 1 MSB
(global)
User Test
Pattern ± LSB
(global)
User Test
Pattern ± MSB
(global)
User Test
Pattern 3 LSB
(global)
User Test
Pattern 3 MSB
(global)
User Test
Pattern 4 LSB
(global)
User Test
Pattern 4 MSB
(global)
PLL Control
(global)
Open
Open
Open
Open
PLL Low
encode
rate
Open
Open
Open
Bit 3 must be
enabled if
ADC clock
enable
rate is less
than 6ꢀ MSPS
Rev. D | Page 35 of 44
AD9644
Data Sheet
Default
Addr
(Hex)
Register
Name
Bit 7
(MSB)
Bit 0
(LSB)
Value
(Hex)
Default/
Comments
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
ꢀx±4
ꢀx±5
ꢀx3A
BIST signature
LSB (local)
BIST signature[7:ꢀ]
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
Read only
BIST signature
MSB (local)
BIST signature[15:8]
Read only
Sync control
(global)
Open
Open
Open
Open
Open
Open
Open
Open
Open
Clock
Clock
divider
sync
Master sync
buffer
enable
divider
next sync
only
enable
JESD±ꢀ4A Configuration Registers
ꢀx5E
JESD±ꢀ4A
quick
configure
Open
ꢀꢀꢀ = default—configuration
determined by other registers
ꢀꢀ1 = two converters using two links
with one lane per link
ꢀ1ꢀ = two converters using one link with
two lanes per link
ꢀxꢀꢀ
Changes
settings of
Address
ꢀx5F to
Address
ꢀx6ꢀ and
Address
ꢀx6E to
Address
ꢀx7±
(global)
ꢀ11 = two converters using one link and
a single lane
1ꢀꢀ to 111: reserved
(self
clearing)
ꢀx5F
JESD±ꢀ4A
lane
assignment
Open
Open
Open
Open
JESD±ꢀ4A serial lane control
ꢀꢀꢀꢀ = one lane per link. Link A: Lane ꢀ sent on Lane A,
Link B: Lane ꢀ Sent on Lane B
ꢀxꢀꢀ
(global)
ꢀꢀꢀ1 = one lane per link. Link A: Lane ꢀ sent on Lane B,
Link B: Lane ꢀ Sent on Lane A.
ꢀꢀ1ꢀ = two lanes per link. Link A: Lane ꢀ, Lane 1 sent on
Lane A, Lane B. Link B disabled.
ꢀꢀ11 = two lanes per link. Link A: Lane ꢀ, Lane 1 sent on
Lane B, Lane A. Link B disabled.
ꢀ1ꢀꢀ = two lanes per link. Link B: Lane ꢀ, Lane 1 sent on
Lane A, Lane B. Link A disabled.
ꢀ1ꢀ1 = two lanes per link. Link B: Lane ꢀ, 1 sent on
Lane B, Lane A. Link A disabled.
ꢀ11ꢀ to 1111: reserved
ꢀx6ꢀ
ꢀx61
ꢀx6±
JESD±ꢀ4A
Link Control
Register 1
(local)
Open
Serial
tail bit
enable
Serial test
sample enable
Serial
lane
synchro
nization
enable
Serial lane alignment
sequence mode
ꢀꢀ = disabled
ꢀ1 = enabled
1ꢀ = reserved
11 = always on test
mode
Frame
Serial
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
alignment
character
insertion
disable
transmit link
powered
down
JESD±ꢀ4A
Link Control
Register ±
(local)
Local DSYNC mode
ꢀꢀ = individual mode
ꢀ1 = global mode
1ꢀ = DSYNC active
mode
DSYNC pin
input inverted
CMOS
DSYNC
input
ꢀ =
LVDS
1 =
Open
Bypass
8b/1ꢀb
encoding
Invert
transmit
bits
Mirror serial
output bits
11 = DSYNC pin
disabled
CMOS
JESD±ꢀ4A
Link Control
Register 3
(local)
Disable
CHKSUM
Open
Link test generation input
selection
Open
Link test generation mode
ꢀꢀꢀ = normal operation
ꢀꢀ = 16-bit data injected at
sample input to the link
ꢀ1 = 1ꢀ-bit data injected at
output of 8b/1ꢀb encoder
1ꢀ = reserved
ꢀꢀ1 = alternating checker board
ꢀ1ꢀ = 1/ꢀ word toggle
ꢀ11 = PN sequence—long
1ꢀꢀ = PN sequence—short
1ꢀ1 = user test pattern data continuous
11ꢀ = user test pattern data single
111 = ramp output
11 = reserved
ꢀx63
ꢀx64
JESD±ꢀ4A
Link Control
Register 4
(local)
Initial lane assignment sequence repeat count
ꢀxꢀꢀ
ꢀxꢀꢀ
JESD±ꢀ4A
device
JESD±ꢀ4A serial device identification (DID) number
identification
number (DID)
(local)
Rev. D | Page 36 of 44
Data Sheet
AD9644
Default
Value
(Hex)
Addr
(Hex)
Register
Name
Bit 7
(MSB)
Bit 0
(LSB)
Default/
Comments
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
ꢀx65
JESD±ꢀ4A
bank
Open
Open
Open
Open
JESD±ꢀ4A serial bank identification number (BID)
ꢀxꢀꢀ
identification
number (BID)
(local)
ꢀx66
JESD±ꢀ4A
lane
identification
number (LID)
for Lane ꢀ
(local)
Open
Open
Open
Open
Open
Open
Open
JESD±ꢀ4A serial lane identification (LID) number for Lane ꢀ
JESD±ꢀ4A serial lane identification (LID) number for Lane 1
ꢀxꢀꢀ
ꢀx67
ꢀx6E
JESD±ꢀ4A
lane
identification
number (LID)
for Lane 1
(local)
Open
ꢀxꢀ1
ꢀx8ꢀ
JESD±ꢀ4A
scrambler
Enable
serial
Open
Open
Open
Open
Lane control
(global)
(SCR) and lane scrambler
ꢀ = one lane
per link (L = 1)
1 = two lanes
per link (L = ±)
(L)
mode
(SCR)
(local)
configuration
register
ꢀx6F
ꢀx7ꢀ
ꢀx71
JESD±ꢀ4A
number of
octets per
frame (F)
(global)
JESD±ꢀ4A number of octets per frame (F)—these bits are calculated based on the equation: F = M × (± ÷ L)
ꢀxꢀ1
ꢀxꢀF
ꢀxꢀꢀ
Read only
JESD±ꢀ4A
number of
frames per
multiframe (K)
(local)
Open
Open
Open
Open
Open
Open
JESD±ꢀ4A number of frames per multiframe (K)
JESD±ꢀ4A
number of
converters per
link (M)
Open
Open
Open
Open
Number of
converters
per link (M)
ꢀ = link
(global)
connected
to one ADC
(M = 1)
1 = link
connected
to two ADCs
(M = ±)
ꢀx7±
JESD ±ꢀ4A
ADC
resolution (N)
and control
bits per
Number of control bits Open
per sample (CS)
ꢀꢀ = no control bits
(CS = ꢀ)
ꢀ1 = one control bit
(CS = 1)
Converter resolution (N) (read only)
ꢀx4D
sample (CS)
(local)
1ꢀ = two control bits
(CS = ±)
11 = unused
ꢀx73
ꢀx74
JESD±ꢀ4A
total bits per
sample (N’)
(global)
Open
Open
Open
Open
Total bits per sample (N’) (read only)
ꢀxꢀF
ꢀxꢀꢀ
Read only
Read only
JESD±ꢀ4A
samples per
converter (S)
frame cycle
(global)
Open
Open
Samples per converter (S) frame cycle (read only)
Always 1 for the AD9644
ꢀx75
JESD±ꢀ4A HD
and CF
Enable
high
Open
Open
Number of control words per frame clock cycle per Link (CF) –
always ꢀ for the AD9644 (read only)
ꢀxꢀꢀ
Read only
configuration
(global)
density
format
(HD = ꢀ,
read only)
Rev. D | Page 37 of 44
AD9644
Data Sheet
Default
Addr
(Hex)
Register
Name
Bit 7
(MSB)
Bit 0
(LSB)
Value
(Hex)
Default/
Comments
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
ꢀx76
ꢀx77
ꢀx78
JESD±ꢀ4A
serial reserved
Field 1 (RES1)
Serial Reserved Field 1 (RES1) – these registers are available for customer use
Serial Reserved Field ± (RES±) – these registers are available for customer use
Serial checksum value for Lane ꢀ (FCHK)
ꢀxꢀꢀ
ꢀxꢀꢀ
ꢀxꢀꢀ
JESD±ꢀ4A
serial reserved
Field ± (RES±)
JESD±ꢀ4A
checksum
value (FCHK)
for Lane ꢀ
(local)
Read only
Read only
ꢀx79
JESD±ꢀ4A
checksum
value (FCHK)
for lane 1
(local)
Serial checksum value for Lane 1 (FCHK)
ꢀxꢀꢀ
1 The channel index register at Address ꢀxꢀ5 should be set to ꢀxꢀ3 (default) when writing to Address ꢀxꢀꢀ.
000: default—configuration determined by other registers
MEMORY MAP REGISTER DESCRIPTIONS
001: two converters using two links with one lane per link
(maximum sample rate = 80 MHz or 155 MHz) Each link
configuration:
For additional information about functions controlled in
Register 0x00 to Register 0x25, see the AN-877 Application Note,
Interfacing to High Speed ADCs via SPI.
M = 1; N’ = 16; CF = 0; K = 16; S = 1; F = 2; L = 1; HD = 0;
Sync Control (Register 0x3A)
Bits[7:3]—Open
010 = two converters using one link with two lanes per link
(Maximum sample rate = 80 MHz or 155 MHz). Each link
configuration:
Bit 2—Clock Divider Next Sync Only
If the master sync buffer enable bit (Address 0x3A, Bit 0) and
the clock divider sync enable bit (Address 0x3A, Bit 1) are high, Bit
2 allows the clock divider to sync to the first sync pulse it receives
and to ignore the rest. The clock divider sync enable bit (Address
0x3A, Bit 1) resets after it syncs.
M = 2; N’ = 16; CF = 0; K = 16; S = 1; F = 2; L = 2; HD = 0;
uses DSYNCA pin for synchronization. Setting this mode sets
Address 0x5F = 0x02 and sets Address 0x60 = 0x14 for Link A
and sets Address 0x60 = 0x01 for Link B.
011 = two converters using one link and a single lane (maxi-
mum sample rate = 78.125 MHz). Each link configuration: M = 2;
N’ = 16; CF = 0; K = 8;S = 1; F = 4; L = 1; HD = 0; uses DSYNCA
pin for synchronization and DOUTA for output signals.
Bit 1—Clock Divider Sync Enable
Bit 1 gates the sync pulse to the clock divider. The sync signal is
enabled when Bit 1 is high and Bit 0 is high. This is continuous
sync mode.
100 to 111: reserved.
Bit 0—Master Sync Buffer Enable
JESD204A Lane Assignment (Register 0x5F)
Bits[7:4]—Reserved
Bit 0 must be high to enable any of the sync functions. If the
sync capability is not used this bit should remain low to
conserve power.
Bits[3:0]—JESD204A Serial Lane Control
These bits set the lane usage. See Figure 62.
JESD204A Quick Configure (Register 0x5E)
Bits[7:3]—Reserved
0000: one lane per link. Link A: Lane 0 sent on Lane A,
Link B: Lane 0 sent on Lane B.
Bits[2:0]—Register Quick Configuration
0001: one lane per link. Link A: Lane 0 sent on Lane B,
Link B: Lane 0 sent on Lane A.
Writes to Bits[2:0] of this register configure the part for the
most popular modes of operation for the JESD204A link. The
intent of this register is to simplify the part setup for typical
serial link operation modes. Writing values other than 0x0 to
this register causes registers throughout the JESD204A memory
map to be updated. Once these registers have been written the
affected JESD204A configuration register reads back with their
new values and can be updated. These bits are self clearing and
always read back as 0b000.
0010: two lanes per link. Link A: Lane 0, one sent on Lane A,
Link B disabled.
0011: two lanes per link. Link A: Lane 0, one sent on Lane B,
Lane A. Link B disabled.
0100: two lanes per link. Link B: Lane 0, one sent on Lane A,
Lane B. Link A disabled.
0101: two lanes per link. Link B: Lane 0, one sent on Lane B,
Lane A. Link A disabled.
0110 to 1111: reserved for future use.
Rev. D | Page 38 of 44
Data Sheet
AD9644
JESD204A Link Control Register 1 (Register 0x60)
Bit 7—Reserved
Bit 3—Open
Bit 2—Bypass 8b/10b Encoding
Bit 6—Serial Tail Bit Enable
If this bit is set the 8b/10b encoding is bypassed and the most
significant bits are set to 0.
If this bit is set, the unused tail bits are padded with a pseudo
random number sequence from a 31-bit LFSR (see JESD204A
5.1.4).
Bit 1—Invert Transmit Bits
Setting this bit inverts the 10 serial output bits. This effectively
inverts the output signals.
Bit 5—Serial Test Sample Enable
If this bit is set, JESD204A test samples are enabled—transport
layer test sample sequence (as specified in JESD204A section
5.1.6.2) is sent on all link lanes.
Bit 0—Mirror Serial Output Bits
Setting this bit reverses the order of the 10b outputs.
JESD204A Link Control Register 3 (Register 0x62)
Bit 4—Serial Lane Synchronization Enable
Bit 7—Disable CHKSUM
If this bit is set, lane synchronization is enabled. Both sides
perform lane sync. Frame alignment character insertion uses
either /K28.3/ or /K28.7/ control characters (see JESD204A
5.3.3.4).
Setting this bit high disables the CHKSUM configuration
parameter (for testing purposes only).
Bit 6—Open
Bits[3:2]—Serial Lane Alignment Sequence Mode
00: initial lane alignment sequence disabled.
01: initial lane alignment sequence enabled.
10: reserved.
Bits[5:4]—Link Test Generation Input Selection
00: 16-bit test generation data injected at sample input to
the link.
01: 10-bit test generation data injected at output of 8b/10b
encoder (at input to PHY).
11: initial lane alignment sequence always on test mode—
JESD204A data link layer test mode where repeated lane alignment
sequence is sent on all lanes.
10: reserved.
11: reserved.
Bit 1—Frame Alignment Character Insertion Disable
Bit 3—Open
Bits[2:0]—Link Test Generation Mode
000: normal operation (test mode disabled).
001: alternating checker board.
010: 1/0 word toggle.
If Bit 1 is set, the frame alignment character insertion is
disabled per JESD204A section 5.3.3.4.
Bit 0—Serial Transmit Link Powered Down
If Bit 0 is set high, the serial transmit link is held in reset with
its clock gated off. The JESD204A transmitter should be
powered down when changing any of the link configuration
bits.
011: PN sequence—long.
100: PN sequence—short.
101: continuous/repeat user test mode—most significant bits
from user pattern (1, 2, 3, 4) placed on the output for 1 clock
cycle and then repeat. (output user pattern 1, 2, 3, 4, 1, 2, 3, 4, 1,
2, 3, 4…).
JESD204A Link Control Register 2 (Register 0x61)
Bits[7:6]—Local DSYNC Mode
00: individual/separate mode. Each link is controlled by a
separate DSYNC pin that independently controls code group
synchronization.
110: single user test mode—most significant bits from user
pattern (1, 2, 3, 4) placed on the output for 1 clock cycle and
then output all zeros. (output user pattern 1, 2, 3, 4, then output
all zeros).
01: global mode. Any DSYNC signal causes the link to begin
code group synchronization.
10: sync active mode. DSYNC signal is active—force code group
synchronization.
111: ramp output.
JESD204A Link Control Register 4 (Register 0x63)
11: DSYNC pin disabled.
Bits[7:0]—Initial Lane Alignment Sequence Repeat Count
Bit 5—DSYNC Pin Input Inverted
If this bit is set, the DSYNC pin of the link is inverted (active high).
Bit 4—CMOS DSYNC Input
Specifies the number of times the initial lane alignment
sequence (ILAS) is repeated. If 0 is programmed the ILAS does
not repeat. If 1 is programmed the ILAS repeat one time and so
on. See Register 0x60, Bits[3:2] to enable the ILAS and for a test
mode to continuously enable the initial lane alignment
sequence.
0: LVDS differential pair DSYNC input (default)
1: CMOS single ended DSYNC input
Rev. D | Page 39 of 44
AD9644
Data Sheet
JESD204A Device Identification Number (DID)
(Register 0x64)
JESD204A Number of Converters Per Link (M)
(Register 0x71)
Bits[7:0]—Serial Device Identification (DID) Number
Bits[7:1]—Reserved
JESD204A Bank Identification Number (BID)
(Register 0x65)
Bit 0—Number of Converters per Link per Device (M).
0: link connected to one ADC. Only primary input used (M = 1).
Bits[7:4]—Open
1: link connected to two ADCs. Primary and secondary inputs
used (M = 2).
Bits[3:0]—Serial Bank Identification (DID) Number
JESD204A Lane Identification Number (LID) for Lane 0
(Register 0x66)
JESD204A ADC Resolution (N) and Control Bits Per
Sample (CS) (Register 0x72)
Bits[7:5]—Open
Bits[7:6]—Number of Control Bits per Sample (CS)
Bits[4:0]—Serial Lane Identification (LID) Number for
Lane 0.
00: no control bits sent per sample (CS = 0).
01: one control bits sent per sample—overrange bit enabled.
(CS = 1).
JESD204A Lane Identification Number (LID) for Lane 1
(Register 0x67)
10: two control bits sent per sample—overflow/underflow bits
enabled (CS = 2).
Bits[7:5]—Open
Bits[4:0]—Serial Lane Identification (LID) Number for
Lane 1.
11: unused.
Bit 5—Open
JESD204A Scrambler (SCR) and Lane Configuration
Registers (Register 0x6E)
Bits[4:0]—Converter Resolution (N)
Bit 7—Enable Serial Scrambler Mode
Setting this bit high enables the scrambler (SCR = 1).
Bits[6:1]—Open
Read only bits showing the converter resolution (reads back 13
(0xD) for 14-bit resolution).
JESD204A Total Bits Per Sample (N’) (Register 0x73)
Bits[7:5]—Open
Bit[0]—Serial Lane Control.
00000: one lane per link (L = 1).
00001: two lanes per link (L = 2).
00010: 11111—reserved.
Bits[4:0]—Total Number of Bits per Sample (N’)
Read only bits showing the total number of bits per sample—1
(reads back 15 (0xF) for 16 bits per sample).
JESD204A Samples Per Converter (S) Frame Cycle
(Register 0x74)
JESD204A Number of Octets Per Frame (F)
(Register 0x6F—Read Only)
Bits[7:5]—Open
Bits[7:0]—Number of Octets per Frame (F)
Bits[4:0]—Samples per Converter Frame Cycle (S)
The readback from this register is calculated from the following
equation: F = (M × 2)/L
Read only bits showing the number of samples per converter
frame cycle −1 (reads back 0 (0x0) for 1 sample per converter
frame).
Valid values for F for the AD9644 are:
F = 2, with M = 1 and L = 1
F = 4, with M = 2 and L = 1
F = 2, with M = 2 and L = 2
JESD204A HD and CF Configuration (Register 0x75)
Bit 7—Enable High Density Format (Read Only)
Read only bit—always 0 in the AD9644.
JESD204A Number of Frames Per Multiframe
(Register 0x70)
Bits[6:5]—Reserved
Bits[4:0]—Number of Control Words per Frame Clock
Cycle per Link (CF)
Bits[7:5]—Reserved
Bits[4:0]—Number of Frames per Multiframe (K).
Read only bits—reads back 0x0 for the AD9644.
Rev. D | Page 4ꢀ of 44
Data Sheet
AD9644
JESD204A Serial Reserved Field 1 (Register 0x76)
JESD204A Serial Checksum Value for Lane 0
(Register 0x78)
Bits[7:0]—Serial Reserved Field 1 (RES1)
Bits[7:0]—Serial Checksum Value for Lane 0
This read/write register is available for customer use.
This read only register is automatically calculated for each lane.
Sum (all link configuration parameters for Lane 0) mode 256.
JESD204A Serial Reserved Field 2 (Register 0x77)
Bits[7:0]—Serial Reserved Field 2 (RES2)
JESD204A Serial Checksum Value for Lane 1
(Register 0x79)
This read/write register is available for customer use.
Bits[7:0]—Serial Checksum Value for Lane 1
This read only register is automatically calculated for each lane.
Sum (all link configuration parameters for Lane 1) mode 256.
Rev. D | Page 41 of 44
AD9644
Data Sheet
APPLICATIONS INFORMATION
The copper plane should have several vias to achieve the lowest
possible resistive thermal path for heat dissipation to flow through
the bottom of the PCB. These vias should be filled or plugged to
prevent solder wicking through the vias, which can compromise
the connection.
DESIGN GUIDELINES
Before starting design and layout of the AD9644 as a system,
it is recommended that the designer become familiar with these
guidelines, which discuss the special circuit connections and
layout requirements that are needed for certain pins.
To maximize the coverage and adhesion between the ADC and
the PCB, a silkscreen should be overlaid to partition the
Power and Ground Recommendations
When connecting power to the AD9644, it is recommended
that two separate 1.8 V supplies be used. Use one supply for
analog (AVDD); use a separate supply for the digital outputs
(DRVDD). For both AVDD and DRVDD several different
decoupling capa-citors should be used to cover both high and
low frequencies. Place these capacitors close to the point of entry
at the PCB level and close to the pins of the part, with minimal
trace length.
continuous plane on the PCB into several uniform sections.
This provides several tie points between the ADC and the PCB
during the reflow process. Using one continuous plane with no
partitions guarantees only one tie point between the ADC and the
PCB. For detailed information about packaging and PCB layout
of chip scale packages, see the AN-772 Application Note, A
Design and Manufacturing Guide for the Lead Frame Chip Scale
Package (LFCSP), at www.analog.com.
A single PCB ground plane should be sufficient when using the
AD9644. With proper decoupling and smart partitioning of the
PCB analog, digital, and clock sections, optimum performance
is easily achieved.
VCMA and VCMB
The VCMA and VCMB pins should be decoupled to ground
with a 0.1 ꢀF capacitor, as shown in Figure 50.
SPI Port
Exposed Paddle Thermal Heat Slug Recommendations
The SPI port should not be active during periods when the full
dynamic performance of the converter is required. Because the
SCLK, CSB, and SDIO signals are typically asynchronous to the
ADC clock, noise from these signals can degrade converter
performance. If the on-board SPI bus is used for other devices,
it may be necessary to provide buffers between this bus and the
AD9644 to keep these signals from transitioning at the converter
inputs during critical sampling periods.
It is mandatory that the exposed paddle on the underside of the
ADC be connected to analog ground (AGND) to achieve the
best electrical and thermal performance. A continuous, exposed
(no solder mask) copper plane on the PCB should mate to the
AD9644 exposed paddle, Pin 0.
Rev. D | Page 4± of 44
Data Sheet
AD9644
OUTLINE DIMENSIONS
DETAIL A
(JEDEC 95)
7.10
0.30
0.23
0.18
7.00 SQ
6.90
PIN 1
INDICATOR
AREA
PIN 1
INDICATOR AR EA
(SEE DETAIL A)
O
P TIONS
37
36
48
1
0.50
BSC
5.65
EXPOSED
PAD
5.50 SQ
5.35
24
13
0.45
0.40
0.35
0.20 MIN
BOTTOM VIEW
5.50 REF
TOP VIEW
END VIEW
0.80
0.75
0.70
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
0.05 MAX
0.02 NOM
COPLANARITY
0.08
SECTION OF THIS DATA SHEET.
SEATING
PLANE
0.20 REF
COMPLIANT TO JEDEC STANDARDS MO-220-WKKD
Figure 72. 48-Lead Lead Frame Chip Scale Package [LFCSP]
7 mm × 7 mm Body and 0.75 mm Package Height
(CP-48-9)
Dimensions shown in millimeters
ORDERING GUIDE
Model1
Temperature Range
Package Description
Package Option
AD9644BCPZ-8ꢀ
AD9644BCPZRL7-8ꢀ
AD9644CCPZ-8ꢀ
AD9644CCPZRL7-8ꢀ
AD9644BCPZ-155
AD9644BCPZRL7-155
AD9644-8ꢀKITZ
AD9644-155KITZ
−4ꢀ°C to +85°C
−4ꢀ°C to +85°C
−4ꢀ°C to +85°C
−4ꢀ°C to +85°C
−4ꢀ°C to +85°C
−4ꢀ°C to +85°C
48-Lead Lead Frame Chip Scale Package [LFCSP]
48-Lead Lead Frame Chip Scale Package [LFCSP]
48-Lead Lead Frame Chip Scale Package [LFCSP]
48-Lead Lead Frame Chip Scale Package [LFCSP]
48-Lead Lead Frame Chip Scale Package [LFCSP]
48-Lead Lead Frame Chip Scale Package [LFCSP]
Evaluation Board
CP-48-9
CP-48-9
CP-48-9
CP-48-9
CP-48-9
CP-48-9
Evaluation Board
1 Z = RoHS Compliant Part.
Rev. D | Page 43 of 44
AD9644
NOTES
Data Sheet
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D09180-9/20(D)
Rev. D | Page 44 of 44
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