Quad, 12-Bit, 170 MSPS/210 MSPS
Serial Output 1.8 V ADC
AD9639
Data Sheet
FEATURES
FUNCTIONAL BLOCK DIAGRAM
AVDD
DRVDD
PDWN
DRGND
AD9639
VIN + A
VIN – A
BUF
SHA
BUF
SHA
BUF
SHA
BUF
SHA
DOUT + A
PIPELINE
ADC
12
PIPELINE
ADC
12
PIPELINE
ADC
12
PIPELINE
ADC
12
VCM A
VIN + B
VIN – B
VCM B
VIN + C
VIN – C
VCM C
VIN + D
VIN – D
DATA SERIALIZER, ENCODER, AND
CML DRIVERS
CHANNEL A
DOUT – A
DOUT + B
CHANNEL B
DOUT – B
DOUT + C
CHANNEL C
DOUT – C
DOUT + D
CHANNEL D
DOUT – D
VCM D
PGM3
REFERENCE
PGM2
RBIAS
DATA RATE
MULTIPLIER
SERIAL
PORT
TEMPOUT
PGM1
PGM0
RESET
APPLICATIONS
SCLK
Communication receivers
Cable head end equipment/M-CMTS
Broadband radios
Wireless infrastructure transceivers
Radar/military-aerospace subsystems
Test equipment
SDI/
SDIO
CSB
SDO
CLK+ CLK–
07973-001
4 ADCs in one package
JESD204 coded serial digital outputs
On-chip temperature sensor
−95 dB channel-to-channel crosstalk
SNR: 65 dBFS with AIN = 85 MHz at 210 MSPS
SFDR: 77 dBc with AIN = 85 MHz at 210 MSPS
Excellent linearity
DNL: ±0.28 LSB (typical)
INL: ±0.7 LSB (typical)
780 MHz full power analog bandwidth
Power dissipation: 325 mW per channel at 210 MSPS
1.25 V p-p input voltage range, adjustable up to 1.5 V p-p
1.8 V supply operation
Clock duty cycle stabilizer
Serial port interface features
Power-down modes
Digital test pattern enable
Programmable header
Programmable pin functions (PGMx, PDWN)
Figure 1.
GENERAL DESCRIPTION
The AD9639 is a quad, 12-bit, 210 MSPS analog-to-digital converter (ADC) with an on-chip temperature sensor and a high
speed serial interface. It is designed to support the digitizing
of high frequency, wide dynamic range signals with an input
bandwidth of up to 780 MHz. The output data is serialized
and presented in packet format, consisting of channel-specific
information, coded samples, and error code correction.
The ADC requires a single 1.8 V power supply. The input clock
can be driven differentially with a sine wave, LVPECL, CMOS,
or LVDS. A clock duty cycle stabilizer allows high performance
at full speed with a wide range of clock duty cycles. The on-chip
reference eliminates the need for external decoupling and can
be adjusted by means of SPI control.
Various power-down and standby modes are supported. The
ADC typically consumes 150 mW per channel with the digital
link still in operation when standby operation is enabled.
Rev. C
Fabricated on an advanced CMOS process, the AD9639 is available in a Pb-free/RoHS-compliant, 72-lead LFCSP package. It is
specified over the industrial temperature range of −40°C to +85°C.
PRODUCT HIGHLIGHTS
1.
2.
3.
4.
5.
6.
Four ADCs are contained in a small, space-saving package.
An on-chip PLL allows users to provide a single ADC
sampling clock; the PLL distributes and multiplies up to
produce the corresponding data rate clock.
The JESD204 coded data rate supports up to 4.2 Gbps
per channel.
The AD9639 operates from a single 1.8 V power supply.
Flexible synchronization schemes and programmable
mode pins are available.
An on-chip temperature sensor is included.
Document Feedback
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rights of third parties that may result from its use. Specifications subject to change without notice. No
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Tel: 781.329.4700 ©2009–2014 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com
AD9639
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Theory of Operation ...................................................................... 17
Applications ....................................................................................... 1
Analog Input Considerations ................................................... 17
Functional Block Diagram .............................................................. 1
Clock Input Considerations ...................................................... 19
General Description ......................................................................... 1
Digital Outputs ........................................................................... 21
Product Highlights ........................................................................... 1
Serial Port Interface (SPI) .............................................................. 29
Revision History ............................................................................... 2
Hardware Interface..................................................................... 29
Specifications..................................................................................... 3
Memory Map .................................................................................. 31
AC Specifications.......................................................................... 4
Reading the Memory Map Table .............................................. 31
Digital Specifications ................................................................... 5
Reserved Locations .................................................................... 31
Switching Specifications .............................................................. 6
Default Values ............................................................................. 31
Timing Diagram ........................................................................... 7
Logic Levels ................................................................................. 31
Absolute Maximum Ratings ............................................................ 8
Applications Information .............................................................. 35
Thermal Resistance ...................................................................... 8
Power and Ground Recommendations ................................... 35
ESD Caution .................................................................................. 8
Exposed Paddle Thermal Heat Slug Recommendations ...... 35
Pin Configuration and Function Descriptions ............................. 9
Outline Dimensions ....................................................................... 36
Typical Performance Characteristics ........................................... 11
Ordering Guide .......................................................................... 36
Equivalent Circuits ......................................................................... 15
REVISION HISTORY
5/14—Rev. B to Rev. C
Changes to Digital Outputs and Timing Section ....................... 27
Changes to Table 15 ........................................................................ 33
7/13—Rev. A to Rev. B
Change to Current Drive Parameter, Table 1 ................................ 3
Updated Outline Dimensions ....................................................... 36
2/10—Rev. 0 to Rev. A
Changes to Differential Input Voltage Range Parameter,
Table 1 ................................................................................................ 3
Changes to Table 7 ............................................................................ 9
Changes to Digital Outputs and Timing Section ....................... 25
Change to Addr. (Hex) 0x01, Table 15 ......................................... 32
5/09—Revision 0: Initial Version
Rev. C | Page 2 of 36
Data Sheet
AD9639
SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, TMIN = −40°C, TMAX = +85°C, 1.25 V p-p differential input, AIN = −1.0 dBFS, DCS enabled, unless
otherwise noted.
Table 1.
Parameter 1
RESOLUTION
ACCURACY
No Missing Codes
Offset Error
Offset Matching
Gain Error
Gain Matching
Differential Nonlinearity (DNL)
Integral Nonlinearity (INL)
ANALOG INPUTS
Differential Input Voltage Range 2
Common-Mode Voltage
Input Capacitance
Input Resistance
Analog Bandwidth, Full Power
Voltage Common Mode (VCM x Pins)
Voltage Output
Current Drive
TEMPERATURE SENSOR OUTPUT
Voltage Output
Current Drive
POWER SUPPLY
AVDD
DRVDD
IAVDD
IDRVDD
Total Power Dissipation
(Including Output Drivers)
Power-Down Dissipation
Standby Dissipation2
CROSSTALK
Overrange Condition 3
Temp
Full
25°C
25°C
25°C
25°C
Full
Full
Min
12
−2.8
AD9639BCPZ-170
Typ
Max
Guaranteed
−2
4
+1
0.9
±0.28
±0.45
±12
12
+4.7
2.7
±0.6
±0.9
Min
12
−2.8
AD9639BCPZ-210
Typ
Max
Guaranteed
−2
4
+1
0.9
±0.28
±0.7
Unit
Bits
±12
12
+4.7
2.7
±0.6
±1.3
mV
mV
% FS
% FS
LSB
LSB
Full
Full
25°C
Full
Full
1.0
1.25
1.4
2
4.3
780
1.5
1.0
1.25
1.4
2
4.3
780
1.5
V p-p
V
pF
kΩ
MHz
Full
Full
1.4
1.44
1
−1.12
739
50
1.5
1.4
1.44
1
−1.12
737
50
1.5
V
mA
mV/°C
mV
µA
1.7
1.7
1.8
1.8
535
98
1.139
1.9
1.9
570
105
1.215
1.7
1.7
1.8
1.8
610
111
1.298
1.9
1.9
650
120
1.386
V
V
mA
mA
W
Full
Full
Full
Full
Full
Full
Full
Full
Full
Full
Full
3
152
−95
−90
3
173
−95
−90
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for definitions and details on how these tests were completed.
AVDD/DRVDD, with link established.
3
Overrange condition is specified as 6 dB above the full-scale input range.
1
2
Rev. C | Page 3 of 36
mW
mW
dB
dB
AD9639
Data Sheet
AC SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, TMIN = −40°C, TMAX = +85°C, 1.25 V p-p differential input, AIN = −1.0 dBFS, DCS enabled, unless
otherwise noted.
Table 2.
Parameter 1
SIGNAL-TO-NOISE RATIO (SNR)
fIN = 84.3 MHz
fIN = 240.3 MHz
SIGNAL-TO-(NOISE + DISTORTION) (SINAD) RATIO
fIN = 84.3 MHz
fIN = 240.3 MHz
EFFECTIVE NUMBER OF BITS (ENOB)
fIN = 84.3 MHz
fIN = 240.3 MHz
WORST HARMONIC (SECOND)
fIN = 84.3 MHz
fIN = 240.3 MHz
WORST HARMONIC (THIRD)
fIN = 84.3 MHz
fIN = 240.3 MHz
WORST OTHER (EXCLUDING SECOND OR THIRD)
fIN = 84.3 MHz
fIN = 240.3 MHz
TWO-TONE INTERMODULATION DISTORTION (IMD)
fIN1 = 140.2 MHz, fIN2 = 141.3 MHz,
AIN1 and AIN2 = −7.0 dBFS
fIN1 = 170.2 MHz, fIN2 = 171.3 MHz,
AIN1 and AIN2 = −7.0 dBFS 2
1
2
AD9639BCPZ-170
Typ
Max
Min
AD9639BCPZ-210
Typ
Max
Temp
Min
Unit
Full
25°C
63.5
64.5
64.1
63.2
64.2
63.2
dB
dB
Full
25°C
63.3
64.4
63.9
62.8
63.9
63
dB
dB
Full
25°C
10.2
10.4
10.3
10.1
10.3
10.2
Bits
Bits
Full
25°C
87.5
82
78.6
86
80
77
dBc
dBc
Full
25°C
79
84
74
76
77
72.6
dBc
dBc
Full
25°C
96
88
86
90
88
83.7
dBc
dBc
25°C
78
25°C
77
dBc
77
dBc
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for definitions and details on how these tests were completed.
Tested at 170 MSPS and 210 MSPS.
Rev. C | Page 4 of 36
Data Sheet
AD9639
DIGITAL SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, TMIN = −40°C, TMAX = +85°C, 1.25 V p-p differential input, AIN = −1.0 dBFS, DCS enabled, unless
otherwise noted.
Table 3.
Parameter 1
CLOCK INPUTS (CLK+, CLK−)
Logic Compliance
Differential Input Voltage
Input Voltage Range
Internal Common-Mode Bias
Input Common-Mode Voltage
High Level Input Voltage (VIH)
Low Level Input Voltage (VIL)
High Level Input Current (IIH)
Low Level Input Current (IIL)
Differential Input Resistance
Input Capacitance
LOGIC INPUTS (PDWN, CSB, SDI/SDIO,
SCLK, RESET, PGMx) 2
Logic 1 Voltage
Logic 0 Voltage
Temp
Full
Full
Full
Full
Full
Full
Full
Full
Full
25°C
25°C
Full
Min
0.2
AVDD −
0.3
1.1
1.2
0
−10
−10
16
AD9639BCPZ-170
Typ
Max
LVPECL/LVDS/CMOS
6
AVDD +
1.6
1.2
AVDD
3.6
0.8
+10
+10
20
24
4
0.8 ×
AVDD
Min
0.2
AVDD −
0.3
1.1
1.2
0
−10
−10
16
AD9639BCPZ-210
Typ
Max
LVPECL/LVDS/CMOS
6
AVDD +
1.6
1.2
AVDD
3.6
0.8
+10
+10
20
24
4
0.8 ×
AVDD
Full
Unit
V p-p
V
V
V
V
µA
µA
kΩ
pF
V
0.2 ×
AVDD
0.2 ×
AVDD
V
Logic 1 Input Current (CSB)
Logic 0 Input Current (CSB)
Logic 1 Input Current
(PDWN, SDI/SDIO, SCLK,
RESET, PGMx)
Logic 0 Input Current
(PDWN, SDI/SDIO, SCLK,
RESET, PGMx)
Input Resistance
Input Capacitance
LOGIC OUTPUT (SDO)
Logic 1 Voltage
Full
Full
Full
0
−60
55
0
−60
55
µA
µA
µA
Full
0
0
µA
25°C
25°C
30
4
30
4
kΩ
pF
Full
1.2
Logic 0 Voltage
DIGITAL OUTPUTS (DOUT + x, DOUT − x)
Logic Compliance
Differential Output Voltage
Common-Mode Voltage
Full
0
1
2
Full
Full
AVDD +
0.3
0.3
CML
0.8
DRVDD/2
1.2
AVDD +
0.3
0.3
0
CML
0.8
DRVDD/2
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for definitions and details on how these tests were completed.
Specified for 13 SDI/SDIO pins on the same SPI bus.
Rev. C | Page 5 of 36
V
V
V
V
AD9639
Data Sheet
SWITCHING SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, TMIN = −40°C, TMAX = +85°C, 1.25 V p-p differential input, AIN = −1.0 dBFS, DCS enabled, unless
otherwise noted.
Table 4.
Parameter 1
CLOCK
Clock Rate
Clock Pulse Width High (tEH)
Clock Pulse Width Low (tEL)
DATA OUTPUT PARAMETERS
Data Output Period or UI
(DOUT + x, DOUT − x)
Data Output Duty Cycle
Data Valid Time
PLL Lock Time (tLOCK)
Wake-Up Time (Standby)
Wake-Up Time (Power-Down) 2
Pipeline Latency
Data Rate per Channel (NRZ)
Deterministic Jitter
Random Jitter
Channel-to-Channel Bit Skew
Channel-to-Channel Packet Skew 3
Output Rise/Fall Time
TERMINATION CHARACTERISTICS
Differential Termination Resistance
APERTURE
Aperture Delay (tA)
Aperture Uncertainty (Jitter)
OUT-OF-RANGE RECOVERY TIME
Temp
Min
Full
Full
Full
100
2.65
2.65
AD9639BCPZ-170
Typ
Max
170
2.9
2.9
Min
100
2.15
2.15
AD9639BCPZ-210
Typ
Max
210
Unit
2.4
2.4
MSPS
ns
ns
Full
1/(20 × fCLK)
1/(20 × fCLK)
Seconds
25°C
25°C
25°C
25°C
25°C
Full
25°C
25°C
25°C
25°C
25°C
25°C
50
0.8
4
250
50
50
0.8
4
250
50
3.4
10
6
0
±1
50
4.2
10
6
0
±1
50
%
UI
µs
ns
μs
CLK cycles
Gbps
ps
ps rms
Seconds
CLK cycles
ps
25°C
100
100
Ω
25°C
25°C
25°C
1.2
0.2
1
1.2
0.2
1
ns
ps rms
CLK cycles
40
40
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for definitions and details on how these tests were completed.
Receiver dependent.
3
See the Serial Data Frame section.
1
2
Rev. C | Page 6 of 36
Data Sheet
AD9639
TIMING DIAGRAM
SAMPLE
N+1
N
N – 40
ANALOG
INPUT SIGNAL
N – 39
N – 38
N – 37
SAMPLE
RATE CLOCK
...
...
SERIAL CODED SAMPLES: N – 40, N – 39, N – 38, N – 37 ...
SERIAL
DATA OUTPUT
...
...
...
Figure 2. Timing Diagram
Rev. C | Page 7 of 36
...
...
...
07973-002
SAMPLE
RATE CLOCK
AD9639
Data Sheet
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 5.
Parameter
AVDD to AGND
DRVDD to DRGND
AGND to DRGND
AVDD to DRVDD
DOUT + x/DOUT − x to DRGND
SDO, SDI/SDIO, CLK±, VIN ± x, VCM x,
TEMPOUT, RBIAS to AGND
SCLK, CSB, PGMx, RESET, PDWN
to AGND
Storage Temperature Range
Operating Temperature Range
Lead Temperature (Soldering, 10 sec)
Junction Temperature
Rating
−0.3 V to +2.0 V
−0.3 V to +2.0 V
−0.3 V to +0.3 V
−2.0 V to +2.0 V
−0.3 V to DRVDD + 0.3 V
−0.3 V to AVDD + 0.3 V
The exposed paddle must be soldered to the ground plane for the
LFCSP package. Soldering the exposed paddle to the printed
circuit board (PCB) increases the reliability of the solder joints,
maximizing the thermal capability of the package.
Table 6. Thermal Resistance
Package Type
72-Lead LFCSP (CP-72-3)
θJA
16.2
θJB
7.9
θJC
0.6
Unit
°C/W
−0.3 V to AVDD + 0.3 V
Typical θJA, θJB, and θJC values are specified for a 4-layer board in
still air. Airflow increases heat dissipation, effectively reducing
θJA. In addition, metal in direct contact with the package leads
from metal traces, through holes, ground, and power planes
reduces θJA.
−65°C to +125°C
−40°C to +85°C
300°C
150°C
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.
ESD CAUTION
Rev. C | Page 8 of 36
Data Sheet
AD9639
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
NC
AVDD
VCM C
AVDD
VIN – C
VIN + C
AVDD
AVDD
AVDD
NC
AVDD
AVDD
AVDD
VIN + B
VIN – B
AVDD
VCM B
AVDD
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
PIN 1
INDICATOR
PIN 0 = EPAD = AGND
AD9639
TOP VIEW
(Not to Scale)
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
NC
PGM0
PGM1
PGM2
PGM3
NC
AVDD
VCM A
AVDD
VIN – A
VIN + A
AVDD
AVDD
AVDD
CSB
SCLK
SDI/SDIO
SDO
NOTES
1. NC = NO CONNECT.
2. 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,
MAXIMIZING THE THERMAL CAPABILITY OF THE PACKAGE.
07973-004
NC
AVDD
AVDD
RESET
DRGND
DRVDD
DOUT + D
DOUT – D
DOUT + C
DOUT – C
DOUT + B
DOUT – B
DOUT + A
DOUT – A
DRVDD
DRGND
PDWN
NC
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
NC
TEMPOUT
RBIAS
AVDD
NC
NC
AVDD
VCM D
AVDD
VIN – D
VIN + D
AVDD
AVDD
AVDD
AVDD
CLK–
CLK+
AVDD
Figure 3. Pin Configuration
Table 7. Pin Function Descriptions
Pin No.
0
Mnemonic
AGND
1, 5, 6, 19, 36, 49, 54,
63, 72
2
3
4, 7, 9, 12, 13, 14, 15,
18, 20, 21, 41, 42, 43,
46, 48, 55, 57, 60, 61,
62, 64, 65, 66, 69, 71
8
10
11
16
17
22
23, 34
24, 33
25
26
27
28
29
30
NC
Description
Analog Ground (Exposed Paddle). The exposed paddle must be soldered to the ground
plane. Soldering the exposed paddle to the PCB increases the reliability of the solder joints,
maximizing the thermal capability of the package.
No Connection.
TEMPOUT
RBIAS
AVDD
Output Voltage to Monitor Temperature.
External Resistor to Set the Internal ADC Core Bias Current.
1.8 V Analog Supply.
VCM D
VIN − D
VIN + D
CLK−
CLK+
RESET
DRGND
DRVDD
DOUT + D
DOUT − D
DOUT + C
DOUT − C
DOUT + B
DOUT − B
Common-Mode Output Voltage Reference.
ADC D Analog Input Complement.
ADC D Analog Input True.
Clock Input Complement.
Clock Input True.
Reset Enable Pin. Resets the digital output timing.
Digital Output Driver Ground.
1.8 V Digital Output Driver Supply.
ADC D Digital Output True.
ADC D Digital Output Complement.
ADC C Digital Output True.
ADC C Digital Output Complement.
ADC B Digital Output True.
ADC B Digital Output Complement.
Rev. C | Page 9 of 36
AD9639
Pin No.
31
32
35
37
38
39
40
44
45
47
50, 51, 52, 53
56
58
59
67
68
70
Data Sheet
Mnemonic
DOUT + A
DOUT − A
PDWN
SDO
SDI/SDIO
SCLK
CSB
VIN + A
VIN − A
VCM A
PGM3, PGM2,
PGM1, PGM0
VCM B
VIN − B
VIN + B
VIN + C
VIN − C
VCM C
Description
ADC A Digital Output True.
ADC A Digital Output Complement.
Power-Down.
Serial Data Output for 4-Wire SPI Interface.
Serial Data Input/Serial Data Input/Output for 3-Wire SPI Interface.
Serial Clock.
Chip Select Bar.
ADC A Analog Input True.
ADC A Analog Input Complement.
Common-Mode Output Voltage Reference.
Optional Pins to be Programmed by Customer.
Common-Mode Output Voltage Reference.
ADC B Analog Input Complement.
ADC B Analog Input True.
ADC C Analog Input True.
ADC C Analog Input Complement.
Common-Mode Output Voltage Reference.
Rev. C | Page 10 of 36
Data Sheet
AD9639
TYPICAL PERFORMANCE CHARACTERISTICS
0
0
AIN = –1.0dBFS
SNR = 64.88dB
ENOB = 10.49 BITS
SFDR = 77.57dBc
–20
AMPLITUDE (dBFS)
–40
–60
–80
–100
–60
–80
–100
0
10
20
30
40
50
FREQUENCY (MHz)
60
70
80
–120
07973-059
–120
0
Figure 4. Single-Tone 32k FFT with fIN = 84.3 MHz, fSAMPLE = 170 MSPS
20
40
60
FREQUENCY (MHz)
80
100
Figure 7. Single-Tone 32k FFT with fIN = 240.3 MHz, fSAMPLE = 210 MSPS
70
0
AIN = –1.0dBFS
SNR = 63.95dB
ENOB = 10.33 BITS
SFDR = 78.90dBc
–20
69
68
67
–40
SNR (dBFS)
AMPLITUDE (dBFS)
–40
07973-062
AMPLITUDE (dBFS)
–20
AIN = –1.0dBFS
SNR = 63.13dB
ENOB = 10.19 BITS
SFDR = 76.07dBc
–60
66
65
64
170MSPS
–80
210MSPS
63
62
–100
0
10
20
30
40
50
FREQUENCY (MHz)
60
70
80
60
50
07973-060
–120
70
Figure 5. Single-Tone 32k FFT with fIN = 240.3 MHz, fSAMPLE = 170 MSPS
110
130 150 170
ENCODE (MSPS)
190
210
230
250
230
250
Figure 8. SNR vs. Encode, fIN = 84.3 MHz
90
0
AIN = –1.0dBFS
SNR = 64.65dB
ENOB = 10.44 BITS
SFDR = 77.54dBc
–20
88
86
84
–40
SFDR (dBFS)
AMPLITUDE (dBFS)
90
07973-067
61
–60
–80
82
170MSPS
80
78
76
74
210MSPS
–100
0
20
40
60
FREQUENCY (MHz)
80
100
70
50
07973-061
–120
Figure 6. Single-Tone 32k FFT with fIN = 84.3 MHz, fSAMPLE = 210 MSPS
Rev. C | Page 11 of 36
70
90
110
130 150 170
ENCODE (MSPS)
190
210
Figure 9. SFDR vs. Encode, fIN = 84.3 MHz
07973-068
72
AD9639
Data Sheet
0
100
AIN1 AND AIN2 = –7.0dBFS
SFDR = 75.44dBc
IMD2 = –78.34dBc
IMD3 = –75.44dBc
90
SFDR (dBFS)
–20
80
SNR/SFDR (dB)
AMPLITUDE (dBFS)
SNR (dBFS)
70
60
50
SFDR (dB)
40
30
–40
–60
–80
SNR (dB)
20
–100
–80
–70
–40
–30
–20
–60
–50
ANALOG INPUT LEVEL (dBFS)
–10
0
–120
07973-069
0
–90
0
Figure 10. SNR/SFDR vs. Analog Input Level, fIN = 84.3 MHz, fSAMPLE = 170 MSPS
40
60
FREQUENCY (MHz)
80
100
Figure 13. Two-Tone 32k FFT with fIN1 = 140.2 MHz and fIN2 = 141.3 MHz,
fSAMPLE = 210 MSPS
0
100
90
SFDR (dBFS)
70
AIN1 AND AIN2 = –7.0dBFS
SFDR = 76.88dBc
IMD2 = –78.75dBc
IMD3 = –78.68dBc
–20
80
SNR (dBFS)
AMPLITUDE (dBFS)
SNR/SFDR (dB)
20
07973-073
10
60
50
SFDR (dB)
40
30
–40
–60
–80
SNR (dB)
20
–100
–80
–70
–40
–30
–20
–60
–50
ANALOG INPUT LEVEL (dBFS)
–10
0
–120
07973-070
0
–90
0
Figure 11. SNR/SFDR vs. Analog Input Level, fIN = 84.3 MHz, fSAMPLE = 210 MSPS
40
60
FREQUENCY (MHz)
80
100
Figure 14. Two-Tone 32k FFT with fIN1 = 170.2 MHz and fIN2 = 171.3 MHz,
fSAMPLE = 210 MSPS
0
95
AIN1 AND AIN2 = –7.0dBFS
SFDR = 77.26dBc
IMD2 = –86.55dBc
IMD3 = –77.26dBc
90
85
AMPLITUDE (dBFS)
–20
AMPLITUDE (dBFS)
20
07973-074
10
–40
–60
–80
80
SFDR (dB)
75
70
65
SNR (dB)
60
55
–100
10
20
30
40
50
FREQUENCY (MHz)
60
70
80
45
07973-072
0
0
Figure 12. Two-Tone 32k FFT with fIN1 = 140.2 MHz and fIN2 = 141.3 MHz,
fSAMPLE = 170 MSPS
50
100
150 200 250 300 350
AIN FREQUENCY (MHz)
400
450
500
07973-077
50
–120
Figure 15. SNR/SFDR Amplitude vs. AIN Frequency, fSAMPLE = 170 MSPS
Rev. C | Page 12 of 36
Data Sheet
AD9639
95
0.8
90
0.6
85
SFDR (dB)
0.2
75
INL (LSB)
AMPLITUDE (dBFS)
0.4
80
70
65
0
–0.2
SNR (dB)
60
–0.4
55
0
50
100
150 200 250 300 350
AIN FREQUENCY (MHz)
400
450
500
–0.8
07973-078
45
0
Figure 16. SNR/SFDR Amplitude vs. AIN Frequency, fSAMPLE = 210 MSPS
500
1000
1500
2000 2500
CODE
3000
3500
4000
4500
07973-119
–0.6
50
Figure 19. INL, fIN = 9.7 MHz, fSAMPLE = 210 MSPS
70
0.4
69
0.2
68
0
67
–0.2
SNR, 210MSPS
66
DNL (LSB)
SNR (dB)
SNR, 170MSPS
65
64
–0.4
–0.6
63
–0.8
62
–20
0
20
40
TEMPERATURE (°C)
60
80
–1.2
07973-080
60
–40
0
Figure 17. SNR vs. Temperature, fIN = 84.3 MHz
500
1000
1500
2000 2500
CODE
3000
3500
4000
4500
07973-120
–1.0
61
Figure 20. DNL, fIN = 9.7 MHz, fSAMPLE = 210 MSPS
90
40,000
INPUT REFERRED NOISE: 0.72 LSB
35,000
85
30,000
NUMBER OF HITS
SFDR, 210MSPS
75
SFDR, 170MSPS
70
25,000
20,000
15,000
10,000
65
–20
0
20
40
TEMPERATURE (°C)
60
80
0
N–3
N–2
N–1
N
N+1
N+2
N+3
MORE
BIN
Figure 18. SFDR vs. Temperature, fIN = 84.3 MHz
Figure 21. Input-Referred Noise Histogram, fSAMPLE = 170 MSPS
Rev. C | Page 13 of 36
07973-106
60
–40
5000
07973-081
SFDR (dB)
80
AD9639
Data Sheet
40,000
90
INPUT REFERRED NOISE: 0.70 LSB
85
35,000
80
75
SNR/SFDR (dB)
NUMBER OF HITS
30,000
25,000
20,000
15,000
SFDR
70
65
SNR
60
55
10,000
50
5000
N–2
N–1
N
N+1
N+2
N+3
MORE
BIN
40
1.0
07973-107
N–3
Figure 22. Input-Referred Noise Histogram, fSAMPLE = 210 MSPS
1.8
Figure 24. SNR/SFDR vs. Analog Input Common-Mode Voltage,
fIN = 84.3 MHz, fSAMPLE = 210 MSPS
0
0
–20
AMPLITUDE (dBFS)
–5
–40
–60
–80
–10
–15
–120
0
20
40
60
80
FREQUENCY (Hz)
100
Figure 23. Noise Power Ratio (NPR), fSAMPLE = 210 MSPS
120
–25
1M
10M
100M
AIN FREQUENCY (Hz)
1G
07973-125
–20
–100
07973-123
AMPLITUDE (dBFS)
1.1
1.2
1.3
1.4
1.5
1.6
1.7
ANALOG INPUT COMMON-MODE VOLTAGE (V)
07973-124
45
0
Figure 25. Full-Power Bandwidth Amplitude vs. AIN Frequency, fSAMPLE = 210 MSPS
Rev. C | Page 14 of 36
Data Sheet
AD9639
EQUIVALENT CIRCUITS
AVDD
AVDD
AVDD
1.2V
10kΩ
CLK+
10kΩ
CLK–
250Ω
SDI/SDIO
07973-005
07973-009
30kΩ
Figure 26. CLK± Inputs
Figure 30. Equivalent SDI/SDIO Input Circuit
AVDD
VIN + x
AVDD
BUF
2kΩ
AVDD
AVDD
BUF
~1.4V
2kΩ
TEMPOUT
VIN – x
07973-010
07973-006
BUF
Figure 27. Analog Inputs
Figure 31. Equivalent TEMPOUT Output Circuit
100Ω
175Ω
RBIAS
175Ω
07973-011
30kΩ
07973-007
SCLK,
PDWN,
PGMx,
RESET
Figure 32. Equivalent RBIAS Input/Output Circuit
Figure 28. Equivalent SCLK, RESET, PDWN, PGMx Input Circuit
AVDD
VCM x
26kΩ
175Ω
1kΩ
07973-008
07973-012
CSB
Figure 33. Equivalent VCM x Output Circuit
Figure 29. Equivalent CSB Input Circuit
Rev. C | Page 15 of 36
AD9639
Data Sheet
AVDD
SDO
DRVDD
RTERM
VCM
DOUT + x
DOUT – x
345Ω
4mA
07973-089
4mA
AVDD
4mA
07973-030
4mA
Figure 35. Equivalent SDO Output Circuit
Figure 34. Equivalent Digital Output Circuit
Rev. C | Page 16 of 36
Data Sheet
AD9639
THEORY OF OPERATION
with each input can help to reduce the peak transient current
injected from the output stage of the driving source.
The AD9639 architecture consists of a differential input buffer and
a front-end sample-and-hold amplifier (SHA) followed by a pipelined switched-capacitor ADC. The quantized outputs from each
stage are combined into a final 12-bit result in the digital correction
logic. The pipelined architecture permits the first stage to operate
on a new input sample while the remaining stages operate on preceding samples. Sampling occurs on the rising edge of the clock.
Each stage of the pipeline, excluding the last, consists of a low
resolution flash ADC connected to a switched-capacitor DAC
and interstage residue amplifier (for example, a multiplying
digital-to-analog converter (MDAC)). The residue amplifier
magnifies the difference between the reconstructed 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.
In addition, low Q inductors or ferrite beads can be placed on
each leg of the input to reduce high differential capacitance at
the analog inputs and, therefore, achieve the maximum bandwidth of the ADC. The use of low Q inductors or ferrite beads is
required when driving the converter front end at high IF
frequencies. Either a shunt capacitor or two single-ended
capacitors can be placed on the inputs to provide a matching
passive network. This ultimately creates a low-pass filter at the
input to limit unwanted broadband noise. See the AN-827
Application Note and the Analog Dialogue article “TransformerCoupled Front-End for Wideband A/D Converters” (Volume 39,
Number 2, April 2005) for more information on this subject. In
general, the precise values depend on the application.
The input stage contains a differential SHA that can be ac- or
dc-coupled in differential or single-ended mode. The output of
the pipeline ADC is put into its final serial format by the data
serializer, encoder, and CML drivers block. The data rate multiplier
creates the clock used to output the high speed serial data at the
CML outputs.
Maximum SNR performance is achieved by setting the ADC to
the largest span in a differential configuration. In the case of the
AD9639, the default input span is 1.25 V p-p. To configure the ADC
for a different input span, see the VREF register (Address 0x18).
For the best performance, an input span of 1.25 V p-p or greater
should be used (see Table 15 for details).
ANALOG INPUT CONSIDERATIONS
Differential Input Configurations
The analog input to the AD9639 is a differential buffer. This
input is optimized to provide superior wideband performance
and requires that the analog inputs be driven differentially. SNR
and SINAD performance degrades if the analog input is driven
with a single-ended signal.
The AD9639 can be driven actively or passively; in either case,
optimum performance is achieved by driving the analog input
differentially. For example, using the ADA4937 differential amplifier to drive the AD9639 provides excellent performance and a
flexible interface to the ADC for baseband and second Nyquist
(~100 MHz IF) applications (see Figure 36 and Figure 37). In either
application, use 1% resistors for good gain matching. Note that the
dc-coupled configuration shows some degradation in spurious performance. For more information, consult the ADA4937 data sheet.
For best dynamic performance, the source impedances driving
VIN + x and VIN − x should be matched such that common-mode
settling errors are symmetrical. These errors are reduced by the
common-mode rejection of the ADC. A small resistor in series
3.3V
1.8V
1.8V
AVDD
DRVDD
205Ω
200Ω
62Ω
SIGNAL
GENERATOR
10kΩ
10kΩ
0.1µF
1.65V
VOCM
24Ω
ADA4937
C
R
–VS
24Ω
27Ω
VIN + x
OPTIONAL C
G = UNITY
200Ω
33Ω
+VS
0.1µF
33Ω
AD9639
ADC INPUT
IMPEDANCE
VIN – x
07973-090
1.25V p-p
0.1µF
205Ω
Figure 36. Differential Amplifier Configuration for AC-Coupled Baseband Applications
3.3V
205Ω
62Ω
0.1µF
33Ω
VIN + x
1.8V
AVDD
DRVDD
+VS
VOCM
200Ω
ADA4937
G = UNITY
AD9639
OPTIONAL C
R
–VS
24Ω
27Ω
33Ω
VIN – x
C
ADC INPUT
IMPEDANCE
VCM x
205Ω
1.4V
Figure 37. Differential Amplifier Configuration for DC-Coupled Baseband Applications
Rev. C | Page 17 of 36
07973-091
SIGNAL
GENERATOR
24Ω
200Ω
1.25V p-p
1.8V
AD9639
Data Sheet
For applications where SNR is a key parameter, differential
transformer coupling is the recommended input configuration
to achieve the true performance of the AD9639 (see Figure 38
to Figure 40).
1.25V p-p
BALUN
1:1 Z
66Ω
0.1µF
0.1μF
*CDIFF
07973-013
L
33Ω
VIN + x
65Ω
07973-017
Single-Ended Input Configuration
AGND
VIN – x
C
ADT1-1WT
1:1 Z RATIO
250Ω
L
2.2pF
33Ω
ADC
AD9639
A single-ended input may provide adequate performance in
cost-sensitive applications. In this configuration, SFDR and
distortion performance can degrade due to input common-mode
swing mismatch. If the application requires a single-ended input
configuration, ensure that the source impedances on each input
are well matched to achieve the best possible performance. A
full-scale input of 1.25 V p-p can be applied to the VIN + x pin
of the AD9639 while the VIN − x pin is terminated. Figure 42
shows a typical single-ended input configuration.
VIN – x
C
07973-014
0.1μF
33Ω
1.25V p-p
Figure 39. Differential Transformer-Coupled Configuration
for Wideband IF Applications
49.9Ω
1.25V p-p
0.1μF
VIN + x
0.1µF
*CDIFF
25Ω
ADT1-1WT
1:1 Z RATIO
VIN – x
Figure 41. Differential Balun-Coupled Configuration
for Wideband IF Applications
ADC
AD9639
Figure 38. Differential Transformer-Coupled Configuration
for Baseband Applications
L
33Ω
ADC
AD9639
BALUN
1:1 Z
VIN + x
*CDIFF IS OPTIONAL
1.25V p-p
4.7pF
C
33Ω
0.1μF
VIN + x
0.1µF
33Ω
ADC
AD9639
VIN – x
C
33Ω
VIN + x
L
33Ω
*CDIFF IS OPTIONAL
ADC
AD9639
Figure 42. Single-Ended Input Configuration
VIN – x
0.1μF
07973-015
250Ω
Figure 40. Differential Transformer-Coupled Configuration
for Narrow-Band IF Applications
Rev. C | Page 18 of 36
07973-016
50Ω
1.25V p-p
0.1µF
33Ω
33Ω
0.1µF
Regardless of the configuration, the value of the shunt capacitor, C,
is dependent on the input frequency and may need to be reduced
or removed.
ADT1-1WT
1:1 Z RATIO
0.1µF
Data Sheet
AD9639
AD9510/AD9511/
AD9512/AD9513/
AD9514/AD9515/
AD9516/AD9518
0.1µF
CLK+
CLK
50Ω*
Figure 43 shows a preferred method for clocking the AD9639. The
low jitter clock source is converted from a single-ended signal
to a differential signal using an RF transformer. The back-toback Schottky diodes across the secondary transformer limit
clock excursions into the AD9639 to approximately 0.8 V p-p
differential. This helps to prevent the large voltage swings of the
clock from feeding through to other portions of the AD9639,
and it preserves the fast rise and fall times of the signal, which
are critical to low jitter performance.
CMOS DRIVER
CLK
0.1µF
CLK+
XFMR
50Ω
Figure 46. Single-Ended 1.8 V CMOS Sample Clock
AD9510/AD9511/
AD9512/AD9513/
AD9514/AD9515/
AD9516/AD9518
ADC
AD9639
Figure 47. Single-Ended 3.3 V CMOS Sample Clock
CLK+
100Ω
PECL DRIVER
0.1µF
CLK–
0.1µF
CLK–
CLK
240Ω
50Ω*
ADC
AD9639
240Ω
07973-019
50Ω*
0.1µF
CLK
*50Ω RESISTORS ARE OPTIONAL.
Figure 44. Differential PECL Sample Clock
AD9510/AD9511/
AD9512/AD9513/
AD9514/AD9515/
AD9516/AD9518
0.1µF
CLK+
0.1µF
CLK+
CLK
0.1µF
CLK–
LVDS DRIVER
100Ω
0.1µF
CLK
ADC
AD9639
CLK–
50Ω*
*50Ω RESISTORS ARE OPTIONAL.
07973-020
50Ω*
ADC
AD9639
*50Ω RESISTOR IS OPTIONAL.
Another option is to ac-couple a differential PECL signal to the
sample clock input pins as shown in Figure 44. The AD9510/
AD9511/AD9512/AD9513/AD9514/AD9515/AD9516/AD9518
family of clock drivers offers excellent jitter performance.
AD9510/AD9511/
AD9512/AD9513/
AD9514/AD9515/
AD9516/AD9518
0.1µF
CLK+
CLK–
07973-018
SCHOTTKY
DIODES:
HSMS-2812
OPTIONAL
100Ω
CLK
0.1µF
Figure 43. Transformer-Coupled Differential Clock
0.1µF
CMOS DRIVER
0.1µF
CLK–
CLK+
CLK
50Ω*
CLK+
0.1µF
39kΩ
*50Ω RESISTOR IS OPTIONAL.
0.1µF
0.1µF
ADC
AD9639
CLK–
0.1µF
0.1µF
0.1µF
CLK+
0.1µF
CLK+
ADT1-1WT, 1:1Z
OPTIONAL
100Ω
07973-021
For optimum performance, the AD9639 sample clock inputs
(CLK+ and CLK−) should be clocked with a differential signal.
This signal is typically ac-coupled to the CLK+ and CLK− pins
via a transformer or capacitors. These pins are biased internally
to 1.2 V and require no additional biasing.
designed to withstand input voltages of up to 3.3 V and,
therefore, offers several selections for the drive logic voltage.
07973-022
CLOCK INPUT CONSIDERATIONS
Figure 45. Differential LVDS Sample Clock
In some applications, it is acceptable to drive the sample clock
inputs with a single-ended CMOS signal. In such applications,
CLK+ should be driven directly from a CMOS gate, and the
CLK− pin should be bypassed to ground with a 0.1 μF capacitor
in parallel with a 39 kΩ resistor (see Figure 46). Although the
CLK+ input circuit supply is AVDD (1.8 V), this input is
Clock Duty Cycle Considerations
Typical high speed ADCs use both clock edges to generate a
variety of internal timing signals. As a result, these ADCs may
be sensitive to the clock duty cycle. Commonly, a 5% tolerance
is required on the clock duty cycle to maintain dynamic performance characteristics.
The AD9639 contains a duty cycle stabilizer (DCS) that retimes
the nonsampling edge, providing an internal clock signal with a
nominal 50% duty cycle. This allows a wide range of clock input
duty cycles without affecting the performance of the AD9639.
When the DCS is on (default), noise and distortion performance
are nearly flat for a wide range of duty cycles. However, some
applications may require the DCS function to be off. If so, keep
in mind that the dynamic range performance may be affected
when operated in this mode. See the Memory Map section for
more details on using this feature.
Jitter in the rising edge of the input is an important concern,
and it is not reduced by the internal stabilization circuit. The
duty cycle control loop does not function for clock rates of less
than 50 MHz nominal. It is not recommended that this ADC
clock be dynamic in nature. Moving the clock around dynamically requires long wait times for the back end serial capture to
retime and resynchronize to the receiving logic. This long time
constant far exceeds the time that it takes for the DCS and the
PLL to lock and stabilize. Only in rare applications would it be
necessary to disable the DCS circuitry in the clock register (see
Address 0x09 in Table 15). Keeping the DCS circuit enabled is
recommended to maximize ac performance.
Rev. C | Page 19 of 36
AD9639
Data Sheet
Clock Jitter Considerations
Power Dissipation
High speed, high resolution ADCs are sensitive to the quality of the
clock input. The degradation in SNR at a given input frequency (fA)
due only to aperture jitter (tJ) can be calculated as follows:
As shown in Figure 49 and Figure 50, the power dissipated by
the AD9639 is proportional to its clock rate. The digital power
dissipation does not vary significantly because it is determined
primarily by the DRVDD supply and the bias current of the
digital output drivers.
Refer to the AN-501 Application Note, the AN-756 Application
Note, and the Analog Dialogue article, “Analog-to-Digital Converter
Clock Optimization: A Test Engineering Perspective” (Volume 42,
Number 2, February 2008) for in-depth information about jitter
performance as it relates to ADCs (visit www.analog.com).
0.7
1.6
IAVDD
0.5
1.2
POWER
1.0
0.4
0.8
0.3
0.6
0.2
0.4
IDRVDD
0.2
0
50
70
90
0.1
110
130
ENCODE (MSPS)
150
2.0
120
1.8
110
1.6
16 BITS
1.4
90
14 BITS
1.2
POWER (W)
100
12 BITS
70
0
170
Figure 49. Supply Current vs. Encode for fIN = 84.3 MHz, fSAMPLE = 170 MSPS
RMS CLOCK JITTER REQUIREMENT
80
CURRENT (mA)
0.6
1.4
0.8
0.7
IAVDD
0.6
0.5
POWER
1.0
0.4
0.8
0.3
10 BITS
60
0.6
0.125 ps
0.25 ps
0.5 ps
1.0 ps
2.0 ps
40
0.2
0.4
IDRVDD
30
1
10
100
ANALOG INPUT FREQUENCY (MHz)
Figure 48. Ideal SNR vs. Input Frequency and Jitter
0.1
0.2
1000
0
50
70
90
110
130
150
ENCODE (MSPS)
170
190
0
210
07973-057
50
07973-024
SNR (dB)
130
0.8
1.8
07973-056
The clock input should be treated as an analog signal in cases
where aperture jitter may affect the dynamic range of the AD9639.
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 are
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 during the last step.
2.0
CURRENT (mA)
In this equation, the rms aperture jitter represents the root mean
square of all jitter sources, including the clock input, analog input
signal, and ADC aperture jitter. IF undersampling applications
are particularly sensitive to jitter (see Figure 48).
POWER (W)
SNR Degradation = 20 × log 10(1/2 × π × fA × tJ)
Figure 50. Supply Current vs. Encode for fIN = 84.3 MHz, fSAMPLE = 210 MSPS
Rev. C | Page 20 of 36
Data Sheet
AD9639
The two resulting octets are optionally scrambled and encoded
into their corresponding 10-bit code. The scrambling function
is controlled by the JESD204 register, Address 0x033[0]. Figure 51
shows how the 12-bit data is taken from the ADC, the tail bits are
added, the two octets are scrambled, and the octets are encoded
into two 10-bit symbols. Figure 52 illustrates the data format.
DIGITAL OUTPUTS
Serial Data Frame
The AD9639 digital output complies with the JEDEC Standard
No. 204 (JESD204), which describes a serial interface for data
converters. JESD204 uses 8B/10B encoding as well as optional
scrambling. K28.5 and K28.7 comma symbols are used for frame
synchronization. The receiver is required to lock onto the serial
data stream and recover the clock with the use of a PLL. (Refer
to IEEE Std 802.3-2002, Section 3, for a complete 8B/10B and
comma symbol description.)
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. A 16-bit parallel implementation is
shown in Figure 54.
The 8B/10B encoding works by taking eight bits of data (an
octet) and encoding them into a 10-bit symbol. In the AD9639,
the 12-bit converter word is broken into two octets. Bit 11
through Bit 4 are in the first octet. The second octet contains
Bit 3 through Bit 0 and four 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 JESD204 register, Address 0x033[3].
FRAME
ASSEMBLER
(ADD TAIL BITS)
SCRAMBLER
1 + x14 + x15
8B/10B
ENCODER
TO
RECEIVER
07973-201
DATA
FROM
ADC
Refer to JEDEC Standard No. 204-April 2006, Section 5.1, for
complete transport layer and data format details and Section 5.2
for a complete explanation of scrambling and descrambling.
Figure 51. ADC Data Output Path
WORD 0[11:4]
SYMBOL 0[9:0]
WORD 0[3:0],TAIL BITS[3:0]
SYMBOL 1[9:0]
WORD 1[11:4]
SYMBOL 2[9:0]
WORD 1[3:0], TAIL BITS[3:0]
SYMBOL 3[9:0]
FRAME 0
TIME
07973-200
FRAME 1
FROM
TRANSMITTER
8B/10B
DECODER
DESCRAMBLER
1 + x14 + x15
FRAME
ALIGNMENT
Figure 53. Required Receiver Data Path
Rev. C | Page 21 of 36
DATA
OUT
07973-202
Figure 52. 12-Bit Data Transmission with Tail Bits
AD9639
Data Sheet
S15
LSB
D
S31
Q
CLK
D31
LSB
S14
D
S30
Q
CLK
D30
S13
D
S29
Q
CLK
SECOND OCTET OF FRAME
S15
D29
S12
D
S28
Q
CLK
S14
D28
S11
D
S27
Q
CLK
S13
D27
S10
D
S26
Q
CLK
S12
D26
S9
D
S25
Q
CLK
S11
D25
S8
D
S24
MSB
Q
CLK
S10
D24
S7
LSB
D
S23
CLK = FRAME CLK
Q
CLK
S9
D23
S6
D
S22
Q
CLK
S8
D22
S5
D
S21
Q
CLK
S7
D21
FIRST OCTET OF FRAME
S4
D
S20
Q
CLK
S6
D20
S3
D
S19
Q
CLK
S5
D19
S2
D
S18
Q
CLK
S4
D18
S1
D
S17
Q
CLK
S3
S16
S2
D16
S1
Figure 54. Parallel Descrambler Required in Receiver
Rev. C | Page 22 of 36
MSB
07973-203
MSB
D17
Data Sheet
AD9639
Initial Synchronization
The serial interface must synchronize to the frame boundaries
before data can be properly decoded. The JESD204 standard has
a synchronization routine to identify the frame boundary. The
PGMx pins are used as SYNC pins by default. When the SYNC
pin is taken low for at least two clock cycles, the AD9639 enters
the synchronization mode. The AD9639 transmits the K28.5
comma symbol until the receiver can identify the frame boundary.
The receiver should then deassert the sync signal (take SYNC
high) and the ADC begins transmitting real data. The first nonK28.5 symbol is the MSB symbol of the 12-bit data.
ICOUNTER = ‘0’;
VCOUNTER = ‘0’;
SYNC_REQUEST = ‘1’;
IF /K28.5/ AND /VALID/ THEN
KCOUNTER = KCOUNTER + ‘1’;
ELSE
KCOUNTER = ‘0’;
END IF;
To minimize skew and time misalignment between each channel
of the digital outputs, the following actions should be taken to
ensure that each channel data frame is within ±1 clock cycle of
the sample clock. For some receiver logic, this is not required.
1.
2.
3.
Full power-down through external PDWN pin.
Chip reset via external RESET pin.
Power-up by releasing external PDWN pin.
RESET
INIT
KCOUNTER < 4
ICOUNTER = 3
SYNC_REQUEST = ‘0’;
KCOUNTER = ‘0’;
IF /INVALID/ THEN
ICOUNTER = ICOUNTER + ‘1’;
VCOUNTER = ‘0’;
ELSE IF /VALID/ THEN
VCOUNTER = VCOUNTER + ‘1’;
END IF;
KCOUNTER = 4
ICOUNTER = ‘0’;
VCOUNTER = ‘0’;
VCOUNTER = 4
CHECK
DATA
/VALID/
VCOUNTER < 4 AND ICOUNTER < 3
07973-204
/INVALID/
Figure 55. Receiver State Machine
Table 8. Variables Used in Receiver State Machine
Variable
ICOUNTER
/INVALID/
/K28.5/
KCOUNTER
SYNC_REQUEST
/VALID/
VCOUNTER
Description
Counter used in the CHECK phase to count the number of invalid symbols.
Asserted by receiver to indicate that the current symbol is an invalid symbol given the current running disparity.
Asserted when the current symbol corresponds to the K28.5 control character.
Counter used in the INIT phase to count the number of valid K28.5 symbols.
Asserted by receiver when loss of code group synchronization is detected.
Asserted by receiver to indicate that the current symbol is a valid symbol given the current running disparity.
Counter used in the CHECK phase to count the number of successive valid symbols.
Rev. C | Page 23 of 36
AD9639
Data Sheet
Continuous Synchronization
Continuous synchronization is part of the JESD204 specification.
The 12-bit word requires two octets to transmit all the data. The
two octets (MSB and LSB) are called a frame. When scrambling
is disabled and the LSB octets of two consecutive frames are the
same, the second LSB octet is replaced by a K28.7 comma symbol.
The receiver is responsible for replacing the K28.7 comma
symbol with the LSB octet of the previous frame.
When scrambling is enabled, any D28.7 symbols found in the
LSB octet of a frame are replaced with K28.7 comma symbols.
The receiver is responsible for replacing the K28.7 comma
symbols with D28.7 symbols when in this mode.
By looking for K28.7 symbols, the receiver can ensure that it is
still synchronized to the frame boundary.
07973-205
IF /K28.7/
/REPLACE_K28.7/
IF (OCOUNTER == PREVIOUS_POSITION) AND /VALID/
/RESET_OCTET_COUNTER/
END IF;
IF /VALID/ | (OCOUNTER == N-1)
PREVIOUS_POSITION = OCOUNTER
END IF;
END IF;
Figure 56. Pseudocode for Data Dependent Frame Synchronization in Receiver
Table 9. Variables and Functions in Data Dependent Frame Synchronization
Variable
N
/K28.7/
OCOUNTER
PREVIOUS_POSITION
/REPLACE_K28.7/
/RESET_OCTET_COUNTER/
/VALID/
Description
Number of octets in frame (octet indexing starts from 0).
Asserted when the current symbol corresponds to the K28.7 control character.
Counter used to mark the position of the current octet in the frame.
Variable that stores the position in the frame of a K28.7 symbol.
Replace K28.7 at the decoder output as follows. When scrambling is disabled, replace K28.7 with the LSB
octet that was decoded at the same position in the previous frame; when scrambling is enabled, replace
K28.7 at the decoder output with D28.7.
Reset octet counter to 0 at reception of next octet.
Asserted by receiver to indicate that the current symbol is a valid symbol given the current running disparity.
Rev. C | Page 24 of 36
Data Sheet
AD9639
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. Alternatively, single-ended 50 Ω termination 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.
The AD9639 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
common mode of the digital output automatically biases itself
to half the supply of DRVDD if dc-coupled connecting is used.
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.
Rev. C | Page 25 of 36
100Ω
DIFFERENTIAL
TRACE PAIR
DRVDD
DOUT + x
100Ω
RECEIVER
DOUT – x
VCM = DRVDD/2
OUTPUT SWING = 400mV p-p
07973-092
The AD9639 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.
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 6 inches and that the differential output traces be close
together and at equal lengths.
Figure 57. DC-Coupled Digital Output Termination Example
VRXCM
DRVDD
100Ω
DIFFERENTIAL
0.1µF TRACE PAIR
DOUT + x
100Ω
OR
RECEIVER
DOUT – x
0.1µF
OUTPUT SWING = 400mV p-p
VCM = Rx VCM
Figure 58. AC-Coupled Digital Output Termination Example
07973-093
Digital Outputs and Timing
AD9639
Data Sheet
HEIGHT1: EYE DIAGRAM
600
TIE1: HISTOGRAM
(y1) –375.023m
(y2) +409.847m
(Δy) +784.671m
100
600
1
TJ@BERI: BATHTUB
3
2
+
+
+
10–2
500
400
200
–200
200
–400
–600
300
10–10
100
10–12
EYE: ALL BITS
OFFSET: 0.015
ULS: 5000: 40044, TOTAL: 12000: 80091
–200
–100
0
100
TIME (ps)
0
200
10–8
–30
–10
10
TIME (ps)
10–14
–0.5
30
0
ULS
07973-094
0
BER
10–6
HITS
VOLTAGE (mV)
10–4
400
0.5
Figure 59. Digital Outputs Data Eye with Trace Lengths Less Than 6 Inches on Standard FR-4, External 100 Ω Terminations at Receiver
HEIGHT1: EYE DIAGRAM
600
TIE1: HISTOGRAM
(y1) –402.016m
(y2) +398.373m
(Δy) +800.389m
300
1
100
2
+
+
3
+
10–2
250
400
TJ@BERI: BATHTUB
0
–200
10–6
BER
HITS
VOLTAGE (mV)
10–4
200
200
150
10–8
100
10–10
–600
50
10–12
EYE: ALL BITS
OFFSET: 0.015
ULS: 5000: 40044, TOTAL 8000: 40044
–200
–100
0
100
TIME (ps)
200
0
–50
0
TIME (ps)
50
10–14
–0.5
0
ULS
0.5
07973-095
–400
Figure 60. Digital Outputs Data Eye with Trace Lengths Greater Than 12 Inches on Standard FR-4, External 100 Ω Terminations at Receiver
Figure 59 shows an example of the digital output (default) data
eye and a time interval error (TIE) jitter histogram with trace
lengths less than 6 inches on standard FR-4 material. Figure 60
shows an example of trace lengths exceeding 12 inches on standard FR-4 material. Note that the TIE jitter histogram reflects
the decrease of the data eye opening as the edge deviates from
the ideal position. It is the user’s responsibility to determine
whether the waveforms meet the timing budget of the design
when the trace lengths exceed 6 inches.
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 15). 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.
The format of the output data is offset binary by default.
Table 10 provides an example of this output coding format.
To change the output data format to twos complement or gray
code, see the Memory Map section (Address 0x14 in Table 15).
Table 10. Digital Output Coding
Code
4095
2048
2047
0
(VIN + x) − (VIN − x),
Input Span = 1.25 V p-p (V)
+0.625
0.00
−0.000305
−0.625
Digital Output Offset
Binary ([D11:D0])
1111 1111 1111
1000 0000 0000
0111 1111 1111
0000 0000 0000
The lowest typical clock rate is 100 MSPS. For clock rates slower
than 100 MSPS, the user can set Bit 3 to 0 in the serial control
register (Address 0x21 in Table 15). This option allows the user
to adjust the PLL loop bandwidth to use clock rates as low as
50 MSPS.
Rev. C | Page 26 of 36
Data Sheet
AD9639
Setting Bit 2 in the output mode register (Address 0x14) allows
the user to invert the digital outputs from their nominal state.
This is not to be confused with inverting the serial stream to an
LSB first mode. In default mode, as shown in Figure 2, the MSB
is first in the data output serial stream. However, this order can
be inverted so that the LSB is first in the data output serial stream.
There are eight digital output test pattern options available that
can be initiated through the SPI (see Table 12 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, depending
on the test pattern selected. Note that some patterns do not
adhere to the data format select option.
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 11 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 11 for the initial values) and
that the AD9639 inverts the bit stream with relation to the ITU-T
standard.
Table 11. PN Sequence
Sequence
PN Sequence Short
PN Sequence Long
Initial
Value
0x0DF
0x29B80A
First Three Output Samples
(MSB First)
0xDF9, 0x353, 0x301
0x591, 0xFD7, 0x0A3
Consult the Memory Map section for information on how to
change these additional digital output timing features through
the SPI.
Table 12. Flexible Output Test Modes
Output Test Mode
Bit Sequence
0000
0001
0010
0011
0100
0101
0110
0111
1
Pattern Name
Off (default)
Midscale short
+Full-scale short
−Full-scale short
Checkerboard
PN sequence long 1
PN sequence short1
One-/zero-word toggle
Digital Output Word 1
N/A
1000 0000 0000
1111 1111 1111
0000 0000 0000
1010 1010 1010
N/A
N/A
1111 1111 1111
Digital Output Word 2
N/A
Same
Same
Same
0101 0101 0101
N/A
N/A
0000 0000 0000
Subject to Data
Format Select
Yes
Yes
Yes
Yes
No
Yes
Yes
No
All test mode options except PN sequence long and PN sequence short can support 8- to 14-bit word lengths to verify data capture to the receiver.
Rev. C | Page 27 of 36
AD9639
Data Sheet
TEMPOUT Pin
The TEMPOUT pin can be used as a coarse temperature sensor
to monitor the internal die temperature of the device. This pin
typically has a 737 mV output with a clock rate of 210 MSPS
and a negative going temperature coefficient of −1.12 mV/°C.
The voltage response of this pin is characterized in Figure 61.
SDO Pin
0.79
The SDO pin is for use in applications that require a 4-wire SPI
mode operation. For normal operation, it should be tied low to
AGND through a 10 kΩ resistor. Alternatively, the device pin
can be left open, and the 345 Ω internal pull-down resistor pulls
this pin low. This pin is only 1.8 V tolerant.
0.77
SDI/SDIO Pin
0.85
0.83
TEMPOUT PIN VOLTAGE (V)
the power-down feature is enabled, the chip continues to function
after PDWN is pulled low without requiring a reset. The AD9639
returns to normal operating mode when the PDWN pin is pulled
low. This pin is only 1.8 V tolerant.
0.81
The SDI/SDIO pin is for use in applications that require either a
4- or 3-wire SPI mode operation. For normal operation, it should
be tied low to AGND through a 10 kΩ resistor. Alternatively,
the device pin can be left open, and the 30 kΩ internal pulldown resistor pulls this pin low. This pin is only 1.8 V tolerant.
0.75
0.73
0.71
0.69
0.67
SCLK Pin
0
10 20 30 40
TEMPERATURE (°C)
50
60
70
80
07973-055
0.65
–40 –30 –20 –10
For normal operation, the SCLK pin should be tied to AGND
through a 10 kΩ resistor. Alternatively, the device pin can be left
open, and the 30 kΩ internal pull-down resistor pulls this pin
low. This pin is only 1.8 V tolerant.
Figure 61. TEMPOUT Pin Voltage vs. Temperature
RBIAS Pin
To set the internal core bias current of the ADC, place a resistor
(nominally equal to 10.0 kΩ) between ground and the RBIAS pin.
The resistor current is derived on chip and sets the AVDD current
of the ADC to a nominal 610 mA at 210 MSPS. Therefore, it is
imperative that a 1% or less tolerance on this resistor be used to
achieve consistent performance.
VCM x Pins
The common-mode output pins can be enabled through the SPI
to provide an external reference bias voltage of 1.4 V for driving
the VIN + x/VIN − x analog inputs. The VCM x pins may be
required when connecting external devices, such as an amplifier
or transformer, to interface to the analog inputs.
RESET Pin
The RESET pin resets the datapath and sets all SPI registers to
their default values. To use this pin, the user must resynchronize
the digital outputs. This pin is only 1.8 V tolerant.
PDWN Pin
When asserted high, the PDWN pin turns off all ADC channels,
including the output drivers. This function can be changed to
a standby function (see Address 0x08 in Table 15). This feature
allows the user to place all channels into standby mode. The
output drivers transmit pseudorandom data until the outputs
are disabled using the output mode register (Address 0x14).
When the PDWN pin is asserted high, the AD9639 is placed into
power-down mode, shutting down the reference, reference buffer,
PLL, and biasing networks. In this state, the ADC typically
dissipates 3 mW. If any of the SPI features are changed before
CSB Pin
For normal operation, the CSB pin should be tied high to AVDD
through a 10 kΩ resistor. Alternatively, the device pin can be left
open, and the 26 kΩ internal pull-up resistor pulls this pin high.
Tying the CSB pin to AVDD causes all information on the SCLK
and SDI/SDIO pins to be ignored. Tying the CSB pin low causes
all information on the SDO and SDI/SDIO pins to be written to
the device. This feature allows the user to reduce the number of
traces to the device if necessary. This pin is only 1.8 V tolerant.
PGMx Pins
All PGMx pins are automatically initialized as synchronization
pins by default. These pins are used to lock the FPGA timing and
data capture during initial startup. These pins are respective to
each channel (PGM3 = Channel A, PGM2 = Channel B, and so
on). The sync (PGMx) pin should be pulled high until this pin
receives a low signal input from the receiver, during which time
the ADC outputs K28.5 comma symbols to indicate the frame
boundary. When the receiver finds the frame boundary, the
sync identification is deasserted low and the ADC outputs the
valid data on the next packet boundary.
When steady state operation for the device is achieved, these pins
can be assigned as a standby option using the PGM mode register
(Address 0x53 in Table 15). All other PGMx pins become global
synchronization pins. This pin is only 1.8 V tolerant.
Rev. C | Page 28 of 36
Data Sheet
AD9639
SERIAL PORT INTERFACE (SPI)
The AD9639 serial port interface allows the user to configure the
converter for specific functions or operations through a structured
register space provided in the ADC. The SPI can provide the
user with additional 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, as
documented in the Memory Map section. Detailed operational
information can be found in the Analog Devices, Inc., AN-877
Application Note, Interfacing to High Speed ADCs via SPI.
Four pins define the SPI: SCLK, SDI/SDIO, SDO, and CSB (see
Table 13). The SCLK pin is used to synchronize the read and
write data presented to the ADC. The SDI/SDIO pin is a dualpurpose pin that allows data to be sent to and read from the
internal ADC memory map registers. The SDO pin is used in
4-wire mode to read back data from the part. The CSB pin is an
active low control that enables or disables the read and write cycles.
Table 13. Serial Port Pins
Pin
SCLK
SDI/SDIO
SDO
CSB
Function
Serial clock. Serial shift clock input. SCLK is used to
synchronize serial interface reads and writes.
Serial data input/output. Dual-purpose pin that
typically serves as an input or an output, depending
on the SPI wire mode, the instruction sent, and the
relative position in the timing frame.
Serial data output. Used only in 4-wire SPI mode.
When set, the SDO pin becomes active. When cleared,
the SDO pin remains in three-state and all read data
is routed to the SDI/SDIO pin.
Chip select bar (active low). This control gates the
read and write cycles.
The falling edge of CSB in conjunction with the rising edge of
SCLK determines the start of the framing sequence. During the
instruction phase, a 16-bit instruction is transmitted, followed
by one or more data bytes, which is determined by Bit Field W0
and Bit Field W1. An example of the serial timing and its definitions can be found in Figure 63 and Table 14.
During normal operation, CSB is used to signal to the device
that SPI commands are to be received and processed. When
CSB is brought low, the device processes SCLK and SDI/SDIO
to execute instructions. Normally, CSB remains low until the
communication cycle is complete. However, if connected to a
slow device, CSB can be brought high between bytes, allowing
older microcontrollers enough time to transfer data into shift
registers. CSB can be stalled when transferring one, two, or three
bytes of data. When W0 and W1 are set to 11, the device enters
streaming mode and continues to process data, either reading
or writing, until CSB is taken high to end the communication
cycle. This allows complete memory transfers without requiring
additional instructions. Regardless of the mode, if CSB is taken
high in the middle of a byte transfer, the SPI state machine is
reset and the device waits for a new instruction.
In addition to the operation modes, the SPI port configuration
influences how the AD9639 operates. For applications that do
not require a control port, the CSB line can be tied high. This
places the SDI/SDIO pin into its secondary mode, as defined in
the SDI/SDIO Pin section. CSB can also be tied low to enable
2-wire mode. When CSB is tied low, SCLK and SDI/SDIO are
the only pins required for communication. Although the device
is synchronized during power-up, the user should ensure that
the serial port remains synchronized with the CSB line when
using this mode. When operating in 2-wire mode, it is recommended that a 1-, 2-, or 3-byte transfer be used exclusively.
Without an active CSB line, streaming mode can be entered but
not exited.
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 to both program the chip and read the
contents of the on-chip memory. If the instruction is a readback
operation, performing a readback causes the SDI/SDIO pin to
change from an input to an output at the appropriate point in
the serial frame.
Data can be sent in MSB first or LSB first mode. MSB first mode
is the default at power-up and can be changed by adjusting the
configuration register (Address 0x00). For more information
about this and other features, see the AN-877 Application Note,
Interfacing to High Speed ADCs via SPI.
HARDWARE INTERFACE
The pins described in Table 13 constitute the physical interface
between the user’s programming device and the serial port of
the AD9639. The SCLK and CSB pins function as inputs when
using the SPI. The SDI/SDIO pin is bidirectional, functioning as
an input during write phases and as an output during readback.
If multiple SDI/SDIO pins share a common connection, ensure
that proper VOH levels are met. Assuming the same load for each
AD9639, Figure 62 shows the number of SDI/SDIO pins that
can be connected together and the resulting VOH level. This
interface is flexible enough to be controlled by either serial
PROMs or PIC microcontrollers, providing the user with an
alternative method, other than a full SPI controller, to program
the ADC (see the AN-812 Application Note).
For users who wish to operate the ADC without using the
SPI, remove any connections from the CSB, SCLK, SDO, and
SDI/SDIO pins. By disconnecting these pins from the control bus,
the ADC can function in its most basic operation. Each of these
pins has an internal termination that floats to its respective level.
Rev. C | Page 29 of 36
1.800
1.795
1.790
1.785
1.780
1.775
1.770
1.765
1.760
1.755
1.750
1.745
1.740
1.735
1.730
1.725
1.720
1.715
0
10
30
20
40
50
60
70
80
90
100
NUMBER OF SDI/SDIO PINS CONNECTED TOGETHER
07973-104
Data Sheet
VOH (V)
AD9639
Figure 62. SDI/SDIO Pin Loading
tDS
tS
tHIGH
tCLK
tH
tDH
tLOW
CSB
DON’T
CARE
SCLK 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
07973-028
SDI/
SDIO
Figure 63. Serial Timing Details
Table 14. Serial Timing Definitions
Parameter
tDS
tDH
tCLK
tS
tH
tHIGH
tLOW
tEN_SDI/SDIO
Timing (ns min)
5
2
40
5
2
16
16
10
tDIS_SDI/SDIO
10
Description
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 clock
Setup time between CSB and SCLK
Hold time between CSB and SCLK
Minimum period that SCLK should be in a logic high state
Minimum period that SCLK should be in a logic low state
Minimum time for the SDI/SDIO pin to switch from an input to an output relative to the
SCLK falling edge (not shown in Figure 63)
Minimum time for the SDI/SDIO pin to switch from an output to an input relative to the
SCLK rising edge (not shown in Figure 63)
Rev. C | Page 30 of 36
Data Sheet
AD9639
MEMORY MAP
READING THE MEMORY MAP TABLE
RESERVED LOCATIONS
Each row in the memory map register table (Table 15) has eight
bit locations. The memory map is divided into three sections: the
chip configuration registers (Address 0x00 to Address 0x02),
the device index and transfer registers (Address 0x05 and
Address 0xFF), and the ADC function registers (Address 0x08
to Address 0x53).
Undefined memory locations should not be written to except
when writing the default values suggested in this data sheet.
Blank cells in Table 15 should be considered reserved bits and
have a 0 written into their registers during power-up.
The leftmost column of the memory map indicates the register
address; the default value is shown in the second rightmost
column. The Bit 7 column is the start of the default hexadecimal
value given. For example, Address 0x09, the clock register, has a
default value of 0x01, meaning that Bit 7 = 0, Bit 6 = 0, Bit 5 = 0,
Bit 4 = 0, Bit 3 = 0, Bit 2 = 0, Bit 1 = 0, and Bit 0 = 1, or 0000 0001
in binary. This setting is the default for the duty cycle stabilizer
in the on condition. By writing a 0 to Bit 0 of this address, followed by 0x01 in the device update register (Address 0xFF[0],
the transfer bit), the duty cycle stabilizer is turned off. It is
important to follow each write sequence with a transfer bit to
update the SPI registers. For more information about this and
other functions, consult the AN-877 Application Note,
Interfacing to High Speed ADCs via SPI.
DEFAULT VALUES
When the AD9639 comes out of a reset, critical registers are
preloaded with default values. These values are indicated in
Table 15.
LOGIC LEVELS
In Table 15, “bit is set” is synonymous with “bit is set to Logic 1”
or “writing Logic 1 for the bit.” Similarly, “bit is cleared” is synonymous with “bit is set to Logic 0” or “writing Logic 0 for the bit.”
Rev. C | Page 31 of 36
AD9639
Data Sheet
Table 15. Memory Map Register
Addr. Register
(MSB)
(Hex) Name
Bit 7
Chip Configuration Registers
SDO active
chip_port_
0x00
(not
config (local,
required,
master)
ignored if
not used)
chip_id
0x01
(global)
0x02
chip_grade
(global)
Bit 6
Bit 5
LSB
first
Soft
reset
Bit 4
ADC A
device_
update (local,
master)
ADC Function Registers
Modes
0x08
(local)
0x09
Clock
(global)
0x0D
test_io
(local)
0x0E
test_bist
(local)
0x0F
adc_input
(local)
Bit 2
Bit 1
16-bit
address
(default
mode for
ADCs)
8-bit chip ID, Bits[2:0]
0x29: AD9639, 12-bit quad
Speed grade
010 = 170 MSPS
100 = 210 MSPS
Device Index and Transfer Registers
device_
0x05
index_A
(global)
0xFF
Bit 3
(LSB)
Bit 0
External PDWN pin
function
00 = full power-down
(default)
01 = standby
Reset PN
sequence
long gen
1 = on
0 = off
(default)
Reset PN
sequence
short gen
1 = on
0 = off
(default)
Rev. C | Page 32 of 36
Default
Value
(Hex)
Comments
0x18
Read only.
Read only.
ADC B
ADC C
Bits are set to
determine
which device
on chip
receives the
next write
command.
The default
is all devices
on chip.
Synchronously
transfers
data from
the master
shift register
to the slave.
ADC D
0x0F
SW
transfer
1 = on
0 = off
(default)
0x00
Power-down mode
00 = chip run
(default)
01 = full power-down
10 = standby
11 = reset
Duty
cycle
stabilize
1 = on
(default)
0 = off
Flexible output test mode
0000 = off (normal operation)
0001 = midscale short
0010 = +FS short
0011 = −FS short
0100 = checkerboard output
0101 = PN 23 sequence
0110 = PN 9 sequence
0111 = 1/0 word toggle
BIST init
BIST
1 = on
enable
0 = off
1 = on
(default)
0 = off
(default)
VCM
Analog
disconnect enable
1 = on
enable
0 = off
1 = on
(default)
0 = off
(default)
0x00
Determines
generic
modes
of chip
operation.
0x01
Turns the
internal
duty cycle
stabilizer
on and off.
0x00
When set,
the test data
is placed on
the output
pins in place
of normal
data.
0x00
When Bit 0
is set, the
built-in selftest function
is initiated.
0x00
Data Sheet
AD9639
Addr.
(Hex)
0x10
Register
Name
Offset
(local)
(MSB)
Bit 7
0x14
output_mode
(local/global)
0x15
output_adjust
(global)
0x18
VREF
(global)
0x21
serial_control
(global)
0x24
misr_lsb
(local)
B7
B6
B5
Bit 3
Bit 2
Bit 1
6-bit device offset adjustment[5:0]
011111 = +31 LSB
011110 = +30 LSB
011101 = +29 LSB
…
000010 = +2 LSB
000001 = +1 LSB
000000 = 0 LSB
111111 = −1 LSB
111110 = −2 LSB
111101 = −3 LSB
…
100001 = −31 LSB
100000 = −32 LSB
Data format select
Output
Output
(global)
invert
enable bar
00 = offset binary
enable
(local)
(default)
(global)
1 = off
01 = twos
1 = on
0 = on
complement
0 = off
(default)
10 = gray code
(default)
Output driver
current[1:0]
00 = 400 mV
(default)
01 = 500 mV
10 = 440 mV
11 = 320 mV
Ref_Vfs[4:0]
Reference full-scale adjust
10000 = 0.98 V p-p
10001 = 1.00 V p-p
10010 = 1.02 V p-p
10011 = 1.04 V p-p
…
11111 = 1.23 V p-p
00000 = 1.25 V p-p
00001 = 1.27 V p-p
…
01110 = 1.48 V p-p
01111 = 1.5 V p-p
PLL
high
encode
rate
mode
(global)
0 = low
rate
1 = high
rate
(default)
B4
B3
B2
B1
B0
0x25
misr_msb
(local)
B15
B14
B13
B12
Bit 6
Bit 5
(LSB)
Bit 0
Bit 4
B11
Rev. C | Page 33 of 36
B10
B9
B8
Default
Value
(Hex)
0x00
Comments
Device
offset trim.
0x00
Configures
the outputs
and the
format of
the data.
0x00
VCM output
adjustments.
0x00
Select
adjustments
for VREF.
0x08
Serial stream
control.
0x00
Least
significant
byte of
MISR.
Read only.
Most
significant
byte of
MISR.
Read only.
0x00
AD9639
Data Sheet
Addr.
(Hex)
0x33
Register
Name
JESD204
(global)
(MSB)
Bit 7
0x53
Dynamic
pgm pins
(global)
pgm_3
00 = sync
01 = Standby A
10 = Standby A and
Standby D
11 = Standby A and
Standby B
Bit 6
Bit 5
Bit 4
pgm_2
00 = sync
01 = Standby B
10 = Standby B and
Standby C
11 = Standby B and
Standby A
Bit 3
Bit 2
Overrange in
LSB of
tail bits
0 = overrange
disabled
(default)
1 = overrange
enabled
pgm_1
00 = sync
01 = Standby C
10 = Standby C and
Standby B
11 = Standby C and
Standby D
Rev. C | Page 34 of 36
Bit 1
(LSB)
Bit 0
Scrambling
enable
0 = scrambling
disabled
(default)
1 = scrambling
enabled
pgm_0
00 = sync
01 = Standby D
10 = Standby D and
Standby A
11 = Standby D and
Standby C
Default
Value
(Hex)
0x00
0x00
Comments
Standby =
ADC core
off, PN23
enabled,
serial
channel
enabled.
Data Sheet
AD9639
APPLICATIONS INFORMATION
POWER AND GROUND RECOMMENDATIONS
When connecting power to the AD9639, it is recommended
that two separate 1.8 V supplies be used: one for analog (AVDD)
and one for digital (DRVDD). If only one supply is available, it
should be routed to the AVDD pin first and then tapped off and
isolated with a ferrite bead or a filter choke preceded by decoupling capacitors for the DRVDD pin. Several different decoupling
capacitors can be used to cover both high and low frequencies.
Locate these capacitors close to the point of entry at the PCB
level and close to the parts, with minimal trace lengths.
A single PCB ground plane should be sufficient when using the
AD9639. With proper decoupling and smart partitioning of the
analog, digital, and clock sections of the PCB, optimum performance can easily be achieved.
EXPOSED PADDLE THERMAL HEAT SLUG
RECOMMENDATIONS
It is required that the exposed paddle on the underside of the
ADC be connected to analog ground (AGND) to achieve the best
electrical and thermal performance of the AD9639. An exposed
continuous copper plane on the PCB should mate to the AD9639
exposed paddle, Pin 0. 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 solder-filled or plugged with nonconductive epoxy.
To maximize the coverage and adhesion between the ADC and
PCB, partition the continuous copper plane into several uniform
sections by overlaying a silkscreen on the PCB. This provides
several tie points between the ADC and PCB during the reflow
process, whereas using one continuous plane with no partitions
guarantees only one tie point. See Figure 64 for a PCB layout
example. For detailed information on packaging and the 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.
07973-029
SILKSCREEN PARTITION
PIN 1 INDICATOR
Figure 64. Typical PCB Layout
Rev. C | Page 35 of 36
AD9639
Data Sheet
OUTLINE DIMENSIONS
10.10
10.00 SQ
9.90
0.60
0.42
0.24
0.60
0.42
0.24
0.30
0.23
0.18
72
55
54
PIN 1
INDICATOR
1
PIN 1
INDICATOR
9.85
9.75 SQ
9.65
0.50
BSC
0.50
0.40
0.30
18
37
BOTTOM VIEW
0.80 MAX
0.65 TYP
0.05 MAX
0.02 NOM
COPLANARITY
0.08
0.20 REF
SEATING
PLANE
0.25 MIN
8.50 REF
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
COMPLIANT TO JEDEC STANDARDS MO-220-VNND-4
06-25-2012-A
1.00
0.85
0.80
19
36
TOP VIEW
12° MAX
8.35
8.20 SQ
8.05
EXPOSED
PAD
Figure 65. 72-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
10 mm × 10 mm Body, Very Thin Quad
(CP-72-3)
Dimensions shown in millimeters
ORDERING GUIDE
Model 1
AD9639BCPZ-170
AD9639BCPZRL-170
AD9639BCPZ-210
AD9639BCPZRL-210
AD9639-210KITZ
1
Temperature Range
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
Package Description
72-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
72-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
72-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
72-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
Evaluation Board
Z = RoHS Compliant Part.
©2009–2014 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D07973-0-5/14(C)
Rev. C | Page 36 of 36
Package Option
CP-72-3
CP-72-3
CP-72-3
CP-72-3
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