AD AD9634 1.8 v analog-to-digital converter Datasheet

FEATURES
FUNCTIONAL BLOCK DIAGRAM
SNR = 69.7 dBFS at 185 MHz AIN and 250 MSPS
SFDR = 87 dBc at 185 MHz AIN and 250 MSPS
−150.6 dBFS/Hz input noise at 185 MHz, −1 dBFS AIN and
250 MSPS
Total power consumption: 360 mW at 250 MSPS
1.8 V supply voltages
LVDS (ANSI-644 levels) outputs
Integer 1-to-8 input clock divider (625 MHz maximum input)
Sample rates of up to 250 MSPS
Internal ADC voltage reference
Flexible analog input range
1.4 V p-p to 2.0 V p-p (1.75 V p-p nominal)
ADC clock duty cycle stabilizer
Serial port control
Energy-saving power-down modes
VIN+
PIPELINE
12-BIT
ADC
VIN–
VCM
DRVDD
AGND
AVDD
12
D0±/D1±
PARALLEL
DDR LVDS
AND
DRIVERS
AD9634
REFERENCE
.
.
.
D10±/D11±
DCO±
OR±
1-TO-8
CLOCK DIVIDER
SERIAL PORT
SCLK
SDIO
CSB
CLK+
CLK–
09996-001
Data Sheet
12-Bit, 170 MSPS/210 MSPS/250 MSPS,
1.8 V Analog-to-Digital Converter
AD9634
Figure 1.
APPLICATIONS
Communications
Diversity radio systems
Multimode digital receivers (3G)
TD-SCDMA, WiMAX, W-CDMA, CDMA2000, GSM, EDGE, LTE
I/Q demodulation systems
Smart antenna systems
General-purpose software radios
Ultrasound equipment
Broadband data applications
GENERAL DESCRIPTION
The AD9634 is a 12-bit, analog-to-digital converter (ADC) with
sampling speeds of up to 250 MSPS. The AD9634 is designed to
support communications applications where low cost, small size,
wide bandwidth, and versatility are desired.
The ADC core features a multistage, differential pipelined
architecture with integrated output error correction logic. The
ADC features wide bandwidth inputs that can support a variety
of user-selectable input ranges. An integrated voltage reference
eases design considerations. A duty cycle stabilizer (DCS) is
provided to compensate for variations in the ADC clock duty cycle,
allowing the converter to maintain excellent performance.
The ADC output data are routed directly to the external 12-bit
LVDS output port.
Flexible power-down options allow significant power savings,
when desired.
Rev. B
Programming for setup and control is accomplished using a
3-wire, SPI-compatible serial interface.
The AD9634 is available in a 32-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.
PRODUCT HIGHLIGHTS
1. Integrated 12-bit, 170 MSPS/210 MSPS/250 MSPS ADC.
2. Fast overrange and threshold detect.
3. Proprietary differential input maintains excellent SNR
performance for input frequencies of up to 350 MHz.
4. 3-pin, 1.8 V SPI port for register programming and readback.
5. Pin compatibility with the AD9642, allowing a simple
migration up to 14 bits, and with the AD6672.
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AD9634* PRODUCT PAGE QUICK LINKS
Last Content Update: 05/10/2017
COMPARABLE PARTS
TOOLS AND SIMULATIONS
View a parametric search of comparable parts.
• Visual Analog
• AD9634 IBIS Model
EVALUATION KITS
• AD9634 Evaluation Board
REFERENCE MATERIALS
• AD9642 Evaluation Board
Technical Articles
• MS-2210: Designing Power Supplies for High Speed ADC
DOCUMENTATION
Application Notes
DESIGN RESOURCES
• AN-1142: Techniques for High Speed ADC PCB Layout
• AD9634 Material Declaration
• AN-282: Fundamentals of Sampled Data Systems
• PCN-PDN Information
• AN-737: How ADIsimADC Models an ADC
• Quality And Reliability
• AN-742: Frequency Domain Response of SwitchedCapacitor ADCs
• Symbols and Footprints
• AN-756: Sampled Systems and the Effects of Clock Phase
Noise and Jitter
DISCUSSIONS
• AN-803: Pin Compatible High Speed ADCs Simplify Design
Tasks
• AN-807: Multicarrier WCDMA Feasibility
• AN-808: Multicarrier CDMA2000 Feasibility
• AN-827: A Resonant Approach to Interfacing Amplifiers to
Switched-Capacitor ADCs
• AN-835: Understanding High Speed ADC Testing and
Evaluation
• AN-878: High Speed ADC SPI Control Software
• AN-905: Visual Analog Converter Evaluation Tool Version
1.0 User Manual
View all AD9634 EngineerZone Discussions.
SAMPLE AND BUY
Visit the product page to see pricing options.
TECHNICAL SUPPORT
Submit a technical question or find your regional support
number.
DOCUMENT FEEDBACK
Submit feedback for this data sheet.
• AN-935: Designing an ADC Transformer-Coupled Front
End
Data Sheet
• AD9634: 12-Bit, 170 MSPS/210 MSPS/250 MSPS, 1.8 V
Analog-to-Digital Converter Data Sheet
User Guides
• AD9634 Quick Start Guide
• UG-386: Evaluating the AD9642/AD9634/AD6672 Analogto-Digital Converters
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AD9634
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
ADC Architecture ...................................................................... 19
Applications ....................................................................................... 1
Analog Input Considerations ................................................... 19
Functional Block Diagram .............................................................. 1
Voltage Reference ....................................................................... 21
General Description ......................................................................... 1
Clock Input Considerations ...................................................... 21
Product Highlights ........................................................................... 1
Power Dissipation and Standby Mode .................................... 23
Revision History ............................................................................... 2
Digital Outputs ........................................................................... 23
Specifications..................................................................................... 3
ADC Overrange (OR)................................................................ 23
ADC DC Specifications ................................................................. 3
Serial Port Interface (SPI) .............................................................. 24
ADC AC Specifications ................................................................. 4
Configuration Using the SPI ..................................................... 24
Digital Specifications ................................................................... 6
Hardware Interface ..................................................................... 24
Switching Specifications ................................................................ 7
SPI Accessible Features .............................................................. 25
Timing Specifications .................................................................. 8
Memory Map .................................................................................. 26
Absolute Maximum Ratings ............................................................ 9
Reading the Memory Map Register Table............................... 26
Thermal Characteristics .............................................................. 9
Memory Map Register Table ..................................................... 27
ESD Caution .................................................................................. 9
Applications Information .............................................................. 29
Pin Configuration and Function Descriptions ........................... 10
Design Guidelines ...................................................................... 29
Typical Performance Characteristics ........................................... 12
Outline Dimensions ....................................................................... 30
Equivalent Circuits ......................................................................... 18
Ordering Guide .......................................................................... 30
Theory of Operation ...................................................................... 19
REVISION HISTORY
12/14—Rev. A to Rev. B
Changes to Features Section............................................................ 1
Changes to Reading the Memory Map Register Table
Section .............................................................................................. 26
Changes to Table 13 ........................................................................ 28
7/14—Rev. 0 to Rev. A
Changes to Features Section............................................................ 1
Changes to Full Power Bandwidth Parameter, Table 2 ................ 5
Deleted Noise Bandwidth Parameter, Table 2............................... 5
7/11—Revision 0: Initial Version
Rev. B | Page 2 of 30
Data Sheet
AD9634
SPECIFICATIONS
ADC DC SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, VIN = −1.0 dBFS differential input, 1.75 V p-p full scale input range,
DCS enabled, unless otherwise noted.
Table 1.
Parameter
RESOLUTION
ACCURACY
No Missing Codes
Offset Error
Gain Error
Differential Nonlinearity (DNL)
Integral Nonlinearity (INL)1
TEMPERATURE DRIFT
Offset Error
Gain Error
INPUT REFERRED NOISE
VREF = 1.0 V
ANALOG INPUT
Input Span
Input Capacitance2
Input Resistance3
Input Common-Mode Voltage
POWER SUPPLIES
Supply Voltage
AVDD
DRVDD
Supply Current
IAVDD1
IDRVDD1
POWER CONSUMPTION
Sine Wave Input (DRVDD = 1.8 V)
Standby Power4
Power-Down Power
Temperature
Full
Min
12
Full
Full
Full
Full
25°C
Full
25°C
AD9634-170
Typ
Max
Min
12
Guaranteed
±11
+2/−11
±0.4
±0.22
±0.4
±0.2
AD9634-210
Typ
Max
Min
12
Guaranteed
±11
+1/−8
±0.4
±0.22
±0.4
±0.2
AD9634-250
Typ
Max
Guaranteed
±11
+3/−7
±0.4
±0.22
±0.6
±0.27
Unit
Bits
mV
%FSR
LSB
LSB
LSB
LSB
Full
Full
±7
±55
±7
±58
±7
±75
ppm/°C
ppm/°C
25°C
0.531
0.391
0.407
LSB rms
Full
Full
Full
Full
1.75
2.5
20
0.9
1.75
2.5
20
0.9
1.75
2.5
20
0.9
V p-p
pF
kΩ
V
Full
Full
1.7
1.7
1.8
1.8
1.9
1.9
Full
Full
123
50
Full
Full
Full
311
50
5
1.7
1.7
1.8
1.8
1.9
1.9
134
54
129
56
340
333
50
5
Measured with a low input frequency, full-scale sine wave.
Input capacitance refers to the effective capacitance between one differential input pin and its complement.
3
Input resistance refers to the effective resistance between one differential input pin and its complement.
4
Standby power is measured with a dc input and the CLK pin inactive (that is, set to AVDD or AGND).
1
2
Rev. B | Page 3 of 30
1.7
1.7
1.8
1.8
1.9
1.9
V
V
139
60
136
64
145
68
mA
mA
360
360
50
5
385
mW
mW
mW
AD9634
Data Sheet
ADC AC SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, VIN = −1.0 dBFS differential input, 1.75 V p-p full-scale input range, unless
otherwise noted.
Table 2.
Parameter1
SIGNAL-TO-NOISE RATIO (SNR)
fIN = 30 MHz
fIN = 90 MHz
fIN = 140 MHz
fIN = 185 MHz
fIN = 220 MHz
SIGNAL-TO-NOISE AND DISTORTION (SINAD)
fIN = 30 MHz
fIN = 90 MHz
fIN = 140 MHz
fIN = 185 MHz
fIN = 220 MHz
EFFECTIVE NUMBER OF BITS (ENOB)
fIN = 30 MHz
fIN = 90 MHz
fIN = 140 MHz
fIN = 185 MHz
fIN = 220 MHz
WORST SECOND OR THIRD HARMONIC
fIN = 30 MHz
fIN = 90 MHz
fIN = 140 MHz
fIN = 185 MHz
fIN = 220 MHz
SPURIOUS-FREE DYNAMIC RANGE (SFDR)
fIN = 30 MHz
fIN = 90 MHz
fIN = 140 MHz
fIN = 185 MHz
fIN = 220 MHz
WORST OTHER (HARMONIC OR SPUR)
fIN = 30 MHz
fIN = 90 MHz
fIN = 140 MHz
fIN = 185 MHz
fIN = 220 MHz
Temperature
25°C
25°C
Full
25°C
25°C
Full
25°C
Min
AD9634-170
Typ
Max
Min
AD9634-210
Typ
Max
Unit
70.2
70.1
70.1
70.0
69.9
69.5
70.0
69.6
69.9
69.7
69.2
69.2
69.3
69.4
69.2
69.2
69.1
69.2
69.0
68.9
68.5
69.1
68.7
69.0
68.7
68.3
68.3
68.4
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
25°C
25°C
25°C
25°C
25°C
11.2
11.2
11.1
11.1
11.0
11.2
11.2
11.2
11.1
11.0
11.2
11.2
11.2
11.1
11.1
Bits
Bits
Bits
Bits
Bits
25°C
25°C
Full
25°C
25°C
Full
25°C
−96
−95
−96
−92
−90
−89
dBc
dBc
dBc
dBc
dBc
dBc
dBc
25°C
25°C
Full
25°C
25°C
Full
25°C
25°C
25°C
Full
25°C
25°C
Full
25°C
25°C
25°C
Full
25°C
25°C
Full
25°C
70.3
70.1
AD9634-250
Min Typ
Max
69.1
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
dBFS
68.8
67.8
68.1
67.8
66.7
−83
−80
−97
−86
−94
−95
−91
−87
−84
−84
−93
96
95
96
92
90
89
97
86
94
95
91
87
84
84
93
−98
−97
−96
−95
−95
−95
−80
83
dBc
dBc
dBc
dBc
dBc
dBc
dBc
80
80
−87
−83
−98
−95
−97
−95
−96
−94
−96
−95
−94
−81
Rev. B | Page 4 of 30
dBc
dBc
dBc
dBc
dBc
dBc
dBc
Data Sheet
Parameter1
TWO-TONE SFDR
fIN = 184.1 MHz, 187.1 MHz (−7 dBFS)
FULL POWER BANDWIDTH
1
AD9634
Temperature
25°C
25°C
Min
AD9634-170
Typ
Max
87
1000
Min
AD9634-210
Typ
Max
89
1000
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for a complete set of definitions.
Rev. B | Page 5 of 30
AD9634-250
Min Typ
Max
Unit
88
1000
dBc
MHz
AD9634
Data Sheet
DIGITAL SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, VIN = −1.0 dBFS differential input, 1.0 V internal reference, DCS enabled, unless
otherwise noted.
Table 3.
Parameter
DIFFERENTIAL CLOCK INPUTS (CLK+, CLK−)
Logic Compliance
Internal Common-Mode Bias
Differential Input Voltage
Input Voltage Range
Input Common-Mode Range
High Level Input Current
Low Level Input Current
Input Capacitance
Input Resistance
LOGIC INPUT (CSB)1
High Level Input Voltage
Low Level Input Voltage
High Level Input Current
Low Level Input Current
Input Resistance
Input Capacitance
LOGIC INPUT (SCLK)2
High Level Input Voltage
Low Level Input Voltage
High Level Input Current
Low Level Input Current
Input Resistance
Input Capacitance
LOGIC INPUTS (SDIO)1
High Level Input Voltage
Low Level Input Voltage
High Level Input Current
Low Level Input Current
Input Resistance
Input Capacitance
DIGITAL OUTPUTS
LVDS Data and OR Outputs (OR+, OR−)
Differential Output Voltage (VOD), ANSI Mode
Output Offset Voltage (VOS), ANSI Mode
Differential Output Voltage (VOD), Reduced Swing Mode
Output Offset Voltage (VOS), Reduced Swing Mode
1
2
Temperature
Min
Full
Full
Full
Full
Full
Full
Full
Full
CMOS/LVDS/LVPECL
0.9
0.3
3.6
AGND
AVDD
0.9
1.4
10
22
−22
−10
4
12
15
18
Full
Full
Full
Full
Full
Full
1.22
0
50
−5
Full
Full
Full
Full
Full
Full
1.22
0
45
−5
Full
Full
Full
Full
Full
Full
1.22
0
45
−5
Full
Full
Full
Full
250
1.15
150
1.15
Pull-up.
Pull-down.
Rev. B | Page 6 of 30
Typ
Max
V
V p-p
V
V
µA
µA
pF
kΩ
2.1
0.6
71
+5
V
V
µA
µA
kΩ
pF
2.1
0.6
70
+5
V
V
µA
µA
kΩ
pF
2.1
0.6
70
+5
V
V
µA
µA
kΩ
pF
450
1.35
280
1.35
mV
V
mV
V
26
2
26
2
26
5
350
1.25
200
1.25
Unit
Data Sheet
AD9634
SWITCHING SPECIFICATIONS
Table 4.
Parameter
CLOCK INPUT PARAMETERS1
Input Clock Rate
Conversion Rate2
DCS Enabled
DCS Disabled
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-2 Mode Through
Divide-by-8 Mode
Aperture Delay (tA)
Aperture Uncertainty (Jitter, tJ)
DATA OUTPUT PARAMETERS1
Data Propagation Delay (tPD)
DCO Propagation Delay (tDCO)
DCO to Data Skew (tSKEW)
Pipeline Delay (Latency)
Wake-Up Time (from Standby)
Wake-Up Time (from Power-Down)
Out-of-Range Recovery Time
1
2
AD9634-170
Min
Typ Max
Temperature
Full
AD9634-210
Min
Typ Max
625
Full
Full
Full
40
10
5.8
Full
Full
Full
2.61
2.76
0.8
Full
Full
2.9
2.9
625
170
170
40
10
4.8
3.19
3.05
2.16
2.28
0.8
2.4
2.4
1.0
0.1
Full
Full
Full
Full
Full
Full
Full
4.1
4.7
0.3
4.7
5.3
0.5
10
10
100
3
AD9634-250
Min Typ Max
210
210
40
10
4
2.64
2.52
1.8
1.9
0.8
1.0
0.1
5.2
5.8
0.7
4.1
4.7
0.3
4.7
5.3
0.5
10
10
100
3
2.0
2.0
625
MHz
250
250
MSPS
MSPS
ns
2.2
2.1
ns
ns
ns
1.0
0.1
5.2
5.8
0.7
4.1
4.7
0.3
4.7
5.3
0.5
10
10
100
3
Unit
ns
ps rms
5.2
5.8
0.7
ns
ns
ns
Cycles
µs
µs
Cycles
See Figure 2.
Conversion rate is the clock rate after the divider.
Timing Diagram
N–1
N+4
tA
N+5
N
N+3
VIN
N+1
tCH
N+2
tCLK
CLK+
CLK–
tDCO
DCO–
DCO+
tSKEW
D0±/D1±
(LSB)
D0
N – 10
D1
N – 10
D0
N–9
D1
N–9
D0
N–8
D1
N–8
D0
N–7
D1
N–7
D0
N–6
D10±/D11±
(MSB)
D10
N – 10
D11
N – 10
D10
N–9
D11
N–9
D10
N–8
D11
N–8
D10
N–7
D11
N–7
D10
N–6
EVEN/ODD
Figure 2. Even/Odd LVDS Mode Data Output Timing
Rev. B | Page 7 of 30
09996-002
tPD
AD9634
Data Sheet
TIMING SPECIFICATIONS
Table 5.
Parameter
SPI TIMING REQUIREMENTS
tDS
tDH
tCLK
tS
tH
tHIGH
tLOW
tEN_SDIO
tDIS_SDIO
Test Conditions/Comments
See Figure 58 for the SPI timing diagram
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
Minimum period that SCLK should be in a logic high state
Minimum period that SCLK should be in a logic low state
Time required for the SDIO pin to switch from an input to an output
relative to the SCLK falling edge (not shown in Figure 58)
Time required for the SDIO pin to switch from an output to an input
relative to the SCLK rising edge (not shown in Figure 58)
Rev. B | Page 8 of 30
Min
Typ
Max
Unit
2
2
40
2
2
10
10
10
ns
ns
ns
ns
ns
ns
ns
ns
10
ns
Data Sheet
AD9634
ABSOLUTE MAXIMUM RATINGS
THERMAL CHARACTERISTICS
Table 6.
Parameter
Electrical
AVDD to AGND
DRVDD to AGND
VIN+, VIN− to AGND
CLK+, CLK− to AGND
VCM to AGND
CSB to AGND
SCLK to AGND
SDIO to AGND
D0±/D1± through D10±/D11±
to AGND
DCO+/DCO− to AGND
OR+/OR− to AGND
Environmental
Operating Temperature Range
(Ambient)
Maximum Junction Temperature
Under Bias
Storage Temperature Range
(Ambient)
Rating
−0.3 V to +2.0 V
−0.3 V to +2.0 V
−0.3 V to AVDD + 0.2 V
−0.3 V to AVDD + 0.2V
−0.3 V to AVDD + 0.2 V
−0.3 V to DRVDD + 0.3 V
−0.3 V to DRVDD + 0.3 V
−0.3 V to DRVDD + 0.3 V
−0.3 V to DRVDD + 0.3 V
−0.3 V to DRVDD + 0.3 V
−0.3 V to DRVDD + 0.3 V
−40°C to +85°C
The exposed paddle must be soldered to the ground plane for the
LFCSP package. Soldering the exposed paddle to the customer
board increases the reliability of the solder joints, maximizing
the thermal capability of the package.
Table 7. Thermal Resistance
Package
Type
32-Lead LFCSP
5 mm × 5 mm
(CP-32-12)
Airflow
Velocity
(m/sec)
0
1.0
2.0
θJA1, 2
37.1
32.4
29.1
θJC1, 3
3.1
θJB1, 4
20.7
Unit
°C/W
°C/W
°C/W
1
Per JEDEC 51-7, plus JEDEC 25-5 2S2P test board.
Per JEDEC JESD51-2 (still air) or JEDEC JESD51-6 (moving air).
3
Per MIL-Std 883, Method 1012.1.
4
Per JEDEC JESD51-8 (still air).
2
Typical θJA is specified for a 4-layer PCB with solid ground plane.
As shown in Table 7, airflow increases 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 the θJA.
150°C
−65°C to +125°C
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
ESD CAUTION
Rev. B | Page 9 of 30
AD9634
Data Sheet
32 AVDD
31 AVDD
30 VIN+
29 VIN–
28 AVDD
27 AVDD
26 VCM
25 DNC
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
1
2
3
4
5
6
7
8
AD9634
TOP VIEW
(Not to Scale)
24 CSB
23 SCLK
22 SDIO
21 DCO+
20 DCO–
19 D10+/D11+ (MSB)
18 D10–/D11– (MSB)
17 DRVDD
NOTES
1. DNC = DO NOT CONNECT. DO NOT CONNECT TO THIS PIN.
2. THE EXPOSED THERMAL PADDLE ON THE BOTTOM OF THE PACKAGE
PROVIDES THE ANALOG GROUND FOR THE PART. THIS EXPOSED
PADDLE MUST BE CONNECTED TO GROUND FOR PROPER OPERATION.
09996-003
D2–/D3–
D2+/D3+
D4–/D5–
D4+/D5+
D6–/D7–
D6+/D7+
D8–/D9–
D8+/D9+
9
10
11
12
13
14
15
16
CLK+
CLK–
AVDD
OR–
OR+
D0–/D1– (LSB)
D0+/D1+ (LSB)
DRVDD
Figure 3. Pin Configuration
Table 8. Pin Function Descriptions
Pin No.
ADC Power Supplies
8, 17
3, 27, 28, 31, 32
0
Mnemonic
Type
Description
DRVDD
AVDD
AGND, Exposed
Paddle
Supply
Supply
Ground
Digital Output Driver Supply (1.8 V Nominal).
Analog Power Supply (1.8 V Nominal).
Analog Ground. The exposed thermal paddle on the bottom of the
package provides the analog ground for the part. This exposed paddle
must be connected to ground for proper operation.
Do No Connect. Do not connect to this pin.
25
ADC Analog
30
29
26
DNC
VIN+
VIN−
VCM
Input
Input
Output
1
2
Digital Outputs
5
4
7
6
10
9
12
11
14
13
16
15
19
18
21
20
CLK+
CLK−
Input
Input
Differential Analog Input Pin (+).
Differential Analog Input Pin (−).
Common-Mode Level Bias Output for Analog Inputs. This pin should be
decoupled to ground using a 0.1 μF capacitor.
ADC Clock Input—True.
ADC Clock Input—Complement.
OR+
OR−
D0+/D1+ (LSB)
D0−/D1− (LSB)
D2+/D3+
D2−/D3−
D4+/D5+
D4−/D5−
D6+/D7+
D6−/D7−
D8+/D9+
D8−/D9−
D10+/D11+ (MSB)
D10−/ D11− (MSB)
DCO+
DCO−
Output
Output
Output
Output
Output
Output
Output
Output
Output
Output
Output
Output
Output
Output
Output
Output
Overrange—True.
Overrange—Complement.
DDR LVDS Output Data 0/Data 1—True (LSB).
DDR LVDS Output Data 0/Data 1—Complement (LSB).
DDR LVDS Output Data 2/Data 3—True.
DDR LVDS Output Data 2/Data 3—Complement.
DDR LVDS Output Data 4/Data 5—True.
DDR LVDS Output Data 4/Data 5—Complement.
DDR LVDS Output Data 6/Data 7—True.
DDR LVDS Output Data 6/Data 7—Complement.
DDR LVDS Output Data 8/Data 9—True.
DDR LVDS Output Data 8/Data 9—Complement.
DDR LVDS Output Data 10/Data 11—True (MSB).
DDR LVDS Output Data 10/Data 11—Complement (MSB).
LVDS Data Clock Output—True.
LVDS Data Clock Output—Complement.
Rev. B | Page 10 of 30
Data Sheet
Pin No.
SPI Control
23
22
24
AD9634
Mnemonic
Type
Description
SCLK
SDIO
CSB
Input
Input/Output
Input
SPI Serial Clock.
SPI Serial Data I/O.
SPI Chip Select (Active Low).
Rev. B | Page 11 of 30
AD9634
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
AVDD = 1.8 V, DRVDD = 1.8 V, sample rate = maximum sample rate per speed grade, DCS enabled, 1.75 V p-p differential input,
VIN = −1.0 dBFS, 32k sample, TA = 25°C, unless otherwise noted.
0
0
–40
–60
SECOND
HARMONIC
THIRD
HARMONIC
–80
–100
–120
–60
THIRD
HARMONIC
SECOND
HARMONIC
–80
–100
20
30
40
50
60
70
80
FREQUENCY (MHz)
–140
0
40
50
60
70
80
120
SFDR (dBFS)
SNR/SFDR (dBc and dBFS)
100
–40
–60
SECOND
HARMONIC
30
Figure 7. AD9634-170 Single-Tone FFT with fIN = 305.1 MHz
170MSPS
185.1MHz @ –1.0dBFS
SNR = 68.5dB (69.5dBFS)
SFDR = 86dBc
–20
20
FREQUENCY (MHz)
Figure 4. AD9634-170 Single-Tone FFT with fIN = 90.1 MHz
0
10
09996-107
10
09996-004
0
THIRD
HARMONIC
–80
–100
80
SNR (dBFS)
60
SFDR (dBc)
40
SNR (dBc)
–120
0
10
20
30
40
50
60
70
80
FREQUENCY (MHz)
0
–100
09996-005
–140
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
INPUT AMPLITUDE (dBFS)
09996-007
20
Figure 8. AD9634-170 Single-Tone SNR/SFDR vs.
Input Amplitude (AIN) with fIN = 90.1 MHz, fS = 170 MSPS
Figure 5. AD9634-170 Single-Tone FFT with fIN = 185.1 MHz
100
0
170MSPS
220.1MHz @ –1.0dBFS
SNR = 68.2dB (69.2dBFS)
SFDR = 84dBc
95
SFDR (dBc)
SNR/SFDR (dBc and dBFS)
–20
–40
–60
THIRD
HARMONIC
SECOND
HARMONIC
–80
–100
90
85
80
75
70
SNR (dBFS)
–120
–140
0
10
20
30
40
50
60
70
80
FREQUENCY (MHz)
09996-006
65
60
60
90
120
150
180
210
240
270
300
330
INPUT FREQUENCY (MHz)
Figure 9. AD9634-170 Single-Tone SNR/SFDR vs. Input Frequency (fIN),
fS = 170 MSPS
Figure 6. AD9634-170 Single-Tone FFT with fIN = 220.1 MHz
Rev. B | Page 12 of 30
09996-008
AMPLITUDE (dBFS)
–40
–120
–140
AMPLITUDE (dBFS)
170MSPS
305.1MHz @ –1.0dBFS
SNR = 67.2dB (68.2dBFS)
SFDR = 86dBc
–20
AMPLITUDE (dBFS)
AMPLITUDE (dBFS)
170MSPS
90.1MHz @ –1.0dBFS
–20 SNR = 69.1dB (70.1dBFS)
SFDR = 93dBc
Data Sheet
AD9634
0
0
–20
–20
SFDR (dBc)
AMPLITUDE (dBFS)
SFDR/IMD3 (dBc and dBFS)
170MSPS
184.12MHz @ –7.0dBFS
187.12MHz @ –7.0dBFS
SFDR = 85dBc (92dBFS)
–40
IMD3 (dBc)
–60
–80
SFDR (dBFS)
–100
–40
–60
–80
–100
–120
INPUT AMPLITUDE (dBFS)
–140
09996-009
–120
–90.0 –81.7 –73.4 –65.1 –56.8 –48.5 –40.2 –31.9 –23.6 –15.3 –7.0
Figure 10. AD9634-170 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with
fIN1 = 89.12 MHz, fIN2 = 92.12 MHz, fS = 170 MSPS
0
10
20
30
40
50
60
70
80
FREQUENCY (MHz)
09996-012
IMD3 (dBFS)
Figure 13. AD9634-170 Two Tone FFT with fIN1 = 184.12 MHz, fIN2 = 187.12 MHz
0
100
–20
95
SFDR (dBc)
SNR/SFDR (dBFS and dBc)
SFDR/IMD3 (dBc and dBFS)
SFDR
–40
IMD3 (dBc)
–60
–80
SFDR (dBFS)
90
85
80
75
SNR
–100
70
INPUT AMPLITUDE (dBFS)
65
40
60
70
80
90 100 110 120 130 140 150 160 170
SAMPLE RATE (MSPS)
Figure 11. AD9634-170 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN)
with fIN1 = 184.12 MHz, fIN2 = 187.12 MHz, fS = 170 MSPS
Figure 14. AD9634-170 Single-Tone SNR/SFDR vs. Sample Rate (fS)
with fIN = 90 MHz
0
14000
170MSPS
89.12MHz @ –7.0dBFS
–20 92.12MHz @ –7.0dBFS
SFDR = 89dBc (96dBFS)
0.531 LSB rms
16,384 TOTAL HITS
12000
–40
10000
NUMBER OF HITS
–60
–80
–100
8000
6000
4000
–120
–140
0
10
20
30
40
50
FREQUENCY (MHz)
60
70
80
09996-011
2000
Figure 12. AD9634-170 Two-Tone FFT with fIN1 = 89.12 MHz, fIN2 = 92.12 MHz
Rev. B | Page 13 of 30
0
N–1
N
N+1
OUTPUT CODE
Figure 15. AD9634-170 Grounded Input Histogram, fS = 170 MSPS
09996-014
AMPLITUDE (dBFS)
50
09996-013
–120
–90.0 –81.7 –73.4 –65.1 –56.8 –48.5 –40.2 –31.9 –23.6 –15.3 –7.0
09996-010
IMD3 (dBFS)
AD9634
Data Sheet
0
0
–40
–60
SECOND
HARMONIC
–40
THIRD
HARMONIC
–80
–100
–60
SECOND
HARMONIC
–100
15
30
45
60
75
90
105
FREQUENCY (MHz)
–140
09996-015
0
0
60
75
90
105
120
SFDR (dBFS)
SNR/SFDR (dBc and dBFS)
100
–40
–60
SECOND
HARMONIC
45
Figure 19. AD9634-210 Single-Tone FFT with fIN = 305.1 MHz
210MSPS
185.1MHz @ –1.0dBFS
SNR = 68.6dB (69.6dBFS)
SFDR = 93dBc
–20
30
FREQUENCY (MHz)
Figure 16. AD9634-210 Single-Tone FFT with fIN = 90.1 MHz
0
15
09996-100
–120
–140
THIRD
HARMONIC
–80
–100
80
SNR (dBFS)
60
SFDR (dBc)
40
SNR (dBc)
–120
0
15
30
45
60
75
90
105
FREQUENCY (MHz)
0
–100
09996-016
–140
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
INPUT AMPLITUDE (dBFS)
09996-018
20
Figure 20. AD9634-210 Single-Tone SNR/SFDR vs. Input Amplitude (AIN) with
fIN = 90.1 MHz, fS = 210 MSPS
Figure 17. AD9634-210 Single-Tone FFT with fIN = 185.1 MHz
100
0
210MSPS
220.1MHz @ –1.0dBFS
SNR = 68.3dB (69.3dBFS)
SFDR = 84dBc
–40
SNR/SFDR (dBc and dBFS)
–20
SFDR (dBc)
95
SECOND
HARMONIC
–60
THIRD
HARMONIC
–80
–100
–120
90
85
80
75
SNR (dBFS)
70
–140
0
15
30
45
60
75
90
105
FREQUENCY (MHz)
09996-017
65
60
60
90
120
150
180
210
240
270
300
330
INPUT FREQUENCY (MHz)
Figure 21. AD9634-210 Single-Tone SNR/SFDR vs. Input Frequency (fIN),
fS = 210 MSPS
Figure 18. AD9634-210 Single-Tone FFT with fIN = 220.1 MHz
Rev. B | Page 14 of 30
09996-019
AMPLITUDE (dBFS)
THIRD
HARMONIC
–80
–120
AMPLITUDE (dBFS)
210MSPS
305.1MHz @ –1.0dBFS
SNR = 67.6dB (68.6dBFS)
SFDR = 83dBc
–20
AMPLITUDE (dBFS)
AMPLITUDE (dBFS)
210MSPS
90.1MHz @ –1.0dBFS
–20 SNR = 69.1dB (70.1dBFS)
SFDR = 92dBc
Data Sheet
AD9634
0
0
–20
–20
SFDR (dBc)
AMPLITUDE (dBFS)
SFDR/IMD3 (dBc and dBFS)
210MSPS
184.12MHz @ –7.0dBFS
187.12MHz @ –7.0dBFS
SFDR = 89dBc (96dBFS)
–40
IMD3 (dBc)
–60
–80
SFDR (dBFS)
–100
–40
–60
–80
–100
–120
INPUT AMPLITUDE (dBFS)
–140
09996-020
–120
–90.0 –81.7 –73.4 –65.1 –56.8 –48.5 –40.2 –31.9 –23.6 –15.3 –7.0
Figure 22. AD9634-210 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with
fIN1 = 89.12 MHz, fIN2 = 92.12 MHz, fS = 210 MSPS
0
15
30
45
60
75
90
105
FREQUENCY (MHz)
09996-023
IMD3 (dBFS)
Figure 25. AD9634-210 Two Tone FFT with fIN1 = 184.12 MHz, fIN2 = 187.12 MHz
0
100
–20
95
SFDR (dBc)
SNR/SFDR (dBFS and dBc)
SFDR/IMD3 (dBc and dBFS)
SFDR
–40
IMD3 (dBc)
–60
–80
SFDR (dBFS)
–100
90
85
80
75
SNR
70
INPUT AMPLITUDE (dBFS)
65
09996-021
–120
–90.0 –81.7 –73.4 –65.1 –56.8 –48.5 –40.2 –31.9 –23.6 –15.3 –7.0
Figure 23. AD9634-210 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with
fIN1 = 184.12 MHz, fIN2 = 187.12 MHz, fS = 210 MSPS
40
16000
–40
12000
14000
NUMBER OF HITS
AMPLITUDE (dBFS)
70
80
90 100 110 120 130 140 150 160 170 180 190 200 210
SAMPLE RATE (MSPS)
210MSPS
89.12MHz @ –7.0dBFS
–20 92.12MHz @ –7.0dBFS
SFDR = 88dBc (95dBFS)
–80
60
Figure 26. AD9634-210 Single-Tone SNR/SFDR vs. Sample Rate (fS) with
fIN = 90 MHz
0
–60
50
09996-024
IMD3 (dBFS)
0.391 LSB rms
16,384 TOTAL HITS
10000
8000
6000
–100
4000
–120
0
15
30
45
60
FREQUENCY (MHz)
75
90
105
Figure 24. AD9634-210 Two-Tone FFT with fIN1 = 89.12 MHz, fIN2 = 92.12 MHz
Rev. B | Page 15 of 30
0
N–1
N
N+1
OUTPUT CODE
Figure 27. AD9634-210 Grounded Input Histogram, fS = 210 MSPS
09996-025
–140
09996-022
2000
AD9634
Data Sheet
0
0
–40
–60
SECOND
HARMONIC
THIRD
HARMONIC
–40
–80
–100
–60
THIRD
HARMONIC
–100
25
50
75
100
125
FREQUENCY (MHz)
–140
09996-026
0
0
75
100
125
Figure 31. AD9634-250 Single-Tone FFT with fIN = 305.1 MHz
120
250MSPS
185.1MHz @ –1.0dBFS
SNR = 68.7dB (69.7dBFS)
SFDR = 87dBc
SFDR (dBFS)
100
SNR/SFDR (dBc and dBFS)
–20
50
FREQUENCY (MHz)
Figure 28. AD9634-250 Single-Tone FFT with fIN = 90.1 MHz
0
25
09996-101
–120
–140
–40
–60
THIRD
HARMONIC
SECOND
HARMONIC
–80
–100
80
SNR (dBFS)
60
SFDR (dBc)
40
SNR (dBc)
–120
0
25
50
75
100
125
FREQUENCY (MHz)
0
–100
09996-027
–140
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
INPUT AMPLITUDE (dBFS)
09996-029
20
Figure 32. AD9634-250 Single-Tone SNR/SFDR vs. Input Amplitude (AIN) with
fIN = 90.1 MHz, fS = 250 MSPS
Figure 29. AD9634-250 Single-Tone FFT with fIN = 185.1 MHz
100
0
250MSPS
220.1MHz @ –1.0dBFS
SNR = 68.3dB (69.3dBFS)
SFDR = 91dBc
95
SFDR (dBc)
SNR/SFDR (dBc and dBFS)
–20
–40
–60
SECOND
HARMONIC
THIRD
HARMONIC
–80
–100
90
85
80
75
70
SNR (dBFS)
–120
–140
0
25
50
75
100
125
FREQUENCY (MHz)
09996-028
65
60
60
90
120
150
180
210
240
270
300
330
INPUT FREQUENCY (MHz)
Figure 33. AD9634-250 Single-Tone SNR/SFDR vs. Input Frequency (fIN),
fS = 250 MSPS
Figure 30. AD9634-250 Single-Tone FFT with fIN = 220.1 MHz
Rev. B | Page 16 of 30
09996-030
AMPLITUDE (dBFS)
SECOND
HARMONIC
–80
–120
AMPLITUDE (dBFS)
250MSPS
305.1MHz @ –1.0dBFS
SNR = 67.4dB (68.4dBFS)
SFDR = 82dBc
–20
AMPLITUDE (dBFS)
AMPLITUDE (dBFS)
250MSPS
90.1MHz @ –1.0dBFS
–20 SNR = 69.0dB (70.0dBFS)
SFDR = 89dBc
Data Sheet
AD9634
0
0
–20
SFDR (dBc)
AMPLITUDE (dBFS)
SFDR/IMD3 (dBc and dBFS)
250MSPS
184.12MHz @ –7.0dBFS
187.12MHz @ –7.0dBFS
SFDR = 88dBc (95dBFS)
–20
–40
IMD3 (dBc)
–60
–80
SFDR (dBFS)
–100
–40
–60
–80
–100
–120
INPUT AMPLITUDE (dBFS)
–140
09996-031
–120
–90.0 –81.7 –73.4 –65.1 –56.8 –48.5 –40.2 –31.9 –23.6 –15.3 –7.0
Figure 34. AD9634-250 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with
fIN1 = 89.12 MHz, fIN2 = 92.12 MHz, fS = 250 MSPS
0
25
50
75
100
125
FREQUENCY (MHz)
09996-034
IMD3 (dBFS)
Figure 37. AD9634-250 Two Tone FFT with fIN1 = 184.12 MHz, fIN2 = 187.12 MHz
0
100
–20
95
SFDR (dBc)
SNR/SFDR (dBFS and dBc)
SFDR/IMD3 (dBc and dBFS)
SFDR
–40
IMD3 (dBc)
–60
–80
SFDR (dBFS)
90
85
80
75
SNR
–100
70
INPUT AMPLITUDE (dBFS)
65
40
100
120
140
160
180
200
220
240
260
Figure 38. AD9634-250 Single-Tone SNR/SFDR vs. Sample Rate (fS)
with fIN = 90 MHz
0
16000
250MSPS
89.12MHz @ –7.0dBFS
92.12MHz @ –7.0dBFS
SFDR = 88dBc (95dBFS)
14000
0.407 LSB rms
16,384 TOTAL HITS
12000
–40
NUMBER OF HITS
AMPLITUDE (dBFS)
80
SAMPLE RATE (MSPS)
Figure 35. AD9634-250 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN)
with fIN1 = 184.12 MHz, fIN2 = 187.12 MHz, fS = 250 MSPS
–20
60
09996-035
–120
–90.0 –81.7 –73.4 –65.1 –56.8 –48.5 –40.2 –31.9 –23.6 –15.3 –7.0
09996-032
IMD3 (dBFS)
–60
–80
–100
10000
8000
6000
4000
–120
0
25
50
75
FREQUENCY (MHz)
100
125
Figure 36. AD9634-250 Two-Tone FFT with fIN1 = 89.12 MHz, fIN2 = 92.12 MHz
Rev. B | Page 17 of 30
0
N–1
N
N+1
OUTPUT CODE
Figure 39. AD9634-250 Grounded Input Histogram, fS = 250 MSPS
09996-036
–140
09996-033
2000
AD9634
Data Sheet
EQUIVALENT CIRCUITS
DRVDD
AVDD
VIN
350Ω
SDIO
09996-040
09996-037
26kΩ
Figure 43. Equivalent SDIO Circuit
Figure 40. Equivalent Analog Input Circuit
AVDD
AVDD
AVDD
0.9V
26kΩ
CLK–
09996-038
CLK+
350Ω
SCLK
15kΩ
09996-041
15kΩ
Figure 44. Equivalent SCLK Input Circuit
Figure 41. Equivalent Clock lnput Circuit
DRVDD
AVDD
26kΩ
V+
DATAOUT–
DATAOUT+
V+
09996-042
09996-039
V–
350Ω
CSB
V–
Figure 45. Equivalent CSB Input Circuit
Figure 42. Equivalent LVDS Output Circuit
Rev. B | Page 18 of 30
Data Sheet
AD9634
THEORY OF OPERATION
Programming and control of the AD9634 are accomplished
using a 3-pin, SPI-compatible serial interface.
ADC ARCHITECTURE
The AD9634 architecture consists of a front-end sample-andhold circuit, 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 and the remaining stages to operate on the 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 digitalto-analog converter (DAC) and an interstage residue amplifier
(MDAC). The MDAC 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.
The input stage 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.
ANALOG INPUT CONSIDERATIONS
The analog input to the AD9634 is a differential switched-capacitor
circuit that has been designed to attain optimum performance
when processing a differential input signal.
The clock signal alternatively switches the input between sample
mode and hold mode (see the configuration shown in Figure 46).
When the input is switched into sample mode, the signal source
must be capable of charging the sampling capacitors and settling
within ½ clock cycle.
In intermediate frequency (IF) undersampling applications, reduce
the shunt capacitors. 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 SwitchedCapacitor ADCs; and the Analog Dialogue article, “TransformerCoupled Front-End for Wideband A/D Converters” for more
information on this subject.
BIAS
S
S
CFB
CS
VIN+
CPAR1
CPAR2
H
S
S
CS
VIN–
CPAR1
CPAR2
S
CFB
S
BIAS
09996-043
The AD9634 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.
Figure 46. Switched-Capacitor Input
For best dynamic performance, match the source impedances
driving VIN+ and VIN− and differentially balance the inputs.
Input Common Mode
The analog inputs of the AD9634 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 commonmode voltage reference is included in the design and is available
from the VCM pin. Using the VCM output 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 VCM pin voltage (typically 0.5 × AVDD). The
VCM pin must be decoupled to ground by a 0.1 µF capacitor,
as described in the Applications Information section. Place this
decoupling capacitor close to the pin to minimize the series
resistance and inductance between the part and this capacitor.
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.
Rev. B | Page 19 of 30
AD9634
Data Sheet
Differential Input Configurations
C2
Optimum performance can be achieved when driving the
AD9634 in a differential input configuration. For baseband
applications, the AD8138, ADA4937-1, and ADA4930-1
differential drivers provide excellent performance and a flexible
interface to the ADC.
R3
33Ω
15Ω
VIN–
33Ω
15Ω
09996-044
15pF
200Ω
0.1µF
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 AD9634. For applications where
SNR is a key parameter, differential double balun coupling is
the recommended input configuration (see Figure 49). In this
configuration, the input is ac-coupled and the VCM voltage 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.
VCM
VIN+
VCM
The signal characteristics must be considered when selecting
a transformer. Most RF transformers saturate at frequencies
below a few megahertz. Excessive signal power can also cause
core saturation, which leads to distortion.
ADC
120Ω
R3
VIN–
Figure 48. Differential Transformer-Coupled Configuration
AVDD
ADA4930-1
ADC
R2
C2
5pF
0.1µF
C1
0.1µF
15pF
90Ω
49.9Ω
R1
200Ω
76.8Ω
VIN+
0.1µF
Figure 47. Differential Input Configuration Using the ADA4930-1
For baseband applications where SNR is a key parameter,
differential transformer coupling is the recommended input
configuration. An example is shown in Figure 48. To bias the
analog input, connect the VCM voltage to the center tap of the
secondary winding of the transformer.
In the double balun and transformer configurations, the value
of the input capacitors and resistors is dependent on the input
frequency 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 the
R1, R2, R3, C1, and C2 components shown in Figure 49.
Table 9. Example RC Network
R1 Series (Ω)
33
15
C1 Differential (pF)
8.2
3.9
R2 Series (Ω)
0
0
C2 Shunt (pF)
15
8.2
R3 Shunt (Ω)
49.9
49.9
C2
R3
R1
0.1µF
0.1µF
2V p-p
R2
VIN+
33Ω
PA
S
S
P
0.1µF
33Ω
0.1µF
C1
R1
ADC
R2
R3
C2
Figure 49. Differential Double Balun Input Configuration
Rev. B | Page 20 of 30
VIN–
VCM
0.1µF
09996-046
Frequency Range (MHz)
0 to 100
100 to 300
09996-045
2V p-p
The output common-mode voltage of the ADA4930-1 is easily
set with the VCM pin of the AD9634 (see Figure 47), and the
driver can be configured in a Sallen-Key filter topology to
provide band limiting of the input signal.
VIN
R2
R1
Data Sheet
AD9634
1000pF
180nH 220nH
1µH
165Ω
VPOS
AD8375
301Ω
5.1pF
1nF
1µH
3.9pF
165Ω
15pF
VCM
1nF
2.5kΩ║2pF
AD9634
68nH
180nH 220nH
09996-047
1000pF
NOTES
1. ALL INDUCTORS ARE COILCRAFT 0603CS COMPONENTS
WITH THE EXCEPTION OF THE 1µH CHOKE INDUCTORS (0603LS).
2. FILTER VALUES SHOWN ARE FOR A 20MHz BANDWIDTH FILTER CENTERED AT 140MHz.
Figure 50. Differential Input Configuration Using the AD8375
VOLTAGE REFERENCE
A stable and accurate voltage reference is built into the AD9634.
The full-scale input range can be adjusted by varying the reference
voltage via SPI. The input span of the ADC tracks reference
voltage changes linearly.
The RF balun configuration is recommended for clock frequencies
between 125 MHz and 625 MHz, and the RF transformer is
recommended for clock frequencies from 10 MHz to 200 MHz.
The back-to-back Schottky diodes across the secondary windings
of the transformer limit clock excursions into the AD9634 to
approximately 0.8 V p-p differential. This limit helps prevent the
large voltage swings of the clock from feeding through to other
portions of the AD9634, while preserving the fast rise and fall times
of the signal, which are critical for low jitter performance.
390pF
CLOCK
INPUT
CLOCK INPUT CONSIDERATIONS
For optimum performance, the AD9634 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 51) and require no
external bias. If the inputs are floated, the CLK− pin is pulled low
to prevent spurious clocking.
Mini-Circuits®
ADT1-1WT, 1:1Z
390pF
XFMR
100Ω
50Ω
390pF
CLK–
SCHOTTKY
DIODES:
HSMS2822
Figure 52. Transformer Coupled Differential Clock (Up to 200 MHz)
AVDD
CLOCK
INPUT
390pF
25Ω
ADC
390pF
CLK+
0.9V
390pF
1nF
CLK–
09996-057
CLK–
SCHOTTKY
DIODES:
HSMS2822
25Ω
4pF
09996-048
Figure 53. Balun-Coupled Differential Clock (Up to 625 MHz)
Figure 51. Equivalent Clock Input Circuit
Clock Input Options
The AD9634 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.
Figure 52 and Figure 53 show two preferable methods for clocking
the AD9634 (at clock rates of up to 625 MHz). A low jitter clock
source is converted from a single-ended signal to a differential
signal using an RF balun or RF transformer.
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 54. The AD9510, AD9511, AD9512, AD9513,
AD9514, AD9515, AD9516, AD9517, AD9518, AD9520, AD9522,
AD9523, AD9524, ADCLK905, ADCLK907, and ADCLK925
clock drivers offer excellent jitter performance.
0.1µF
CLOCK
INPUT
CLOCK
INPUT
0.1µF
CLK+
AD95xx,
ADCLKxxx
0.1µF
PECL DRIVER
100Ω
ADC
0.1µF
CLK–
50kΩ
50kΩ
240Ω
240Ω
Figure 54. Differential PECL Sample Clock (Up to 625 MHz)
Rev. B | Page 21 of 30
09996-051
CLK+
4pF
ADC
CLK+
09996-056
An alternative to using a transformer-coupled input at
frequencies in the second Nyquist zone is to use an amplifier
with variable gain. The AD8375 digital variable gain amplifier
(DVGA) provides good performance for driving the AD9634.
Figure 50 shows an example of the AD8375 driving the AD9634
through a band-pass antialiasing filter.
AD9634
Data Sheet
Jitter Considerations
A third option is to ac couple a differential LVDS signal to the
sample clock input pins, as shown in Figure 55. The AD9510,
AD9511, AD9512, AD9513, AD9514, AD9515, AD9516, AD9517,
AD9518, AD9520, AD9522, AD9523, AD9524 clock drivers offer
excellent jitter performance.
0.1µF
SNRHF = −10 log[(2π × fIN × tJRMS)2 + 10 (  SNRLF /10) ]
0.1µF
CLOCK
INPUT
CLK+
AD95xx
0.1µF
LVDS DRIVER
100Ω
ADC
0.1µF
CLK–
50kΩ
09996-052
CLOCK
INPUT
High speed, high resolution ADCs are sensitive to the quality
of the clock input. The degradation in SNR at a given input
frequency (fIN) due to jitter (tJ) can be calculated by
50kΩ
In the equation, the rms aperture jitter represents the rootmean-square of all jitter sources, which include the clock input,
the analog input signal, and the ADC aperture jitter specification.
IF undersampling applications are particularly sensitive to jitter,
as shown in Figure 56.
80
Figure 55. Differential LVDS Sample Clock (Up to 625 MHz)
75
Input Clock Divider
70
SNR (dBFS)
The AD9634 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 DCS is enabled by default on
power-up.
65
60
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. Commonly, a ±5% tolerance is required on the
clock duty cycle to maintain dynamic performance characteristics.
The AD9634 contains a 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 performance of the
AD9634.
Jitter on the rising edge of the input clock is still of paramount
concern and is not reduced by the duty cycle stabilizer. The duty
cycle control loop does not function for clock rates less than
40 MHz nominally. The loop has a time constant associated
with it that must be considered when the clock rate may 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 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.
0.05ps
0.2ps
0.5ps
1ps
1.5ps
MEASURED
55
50
1
10
100
1000
INPUT FREQUENCY (MHz)
09996-054
Clock Duty Cycle
Figure 56. AD9634-250 SNR vs. Input Frequency and Jitter
In cases where aperture jitter may affect the dynamic range of the
AD9634, treat the clock input as an analog signal. In addition,
use separate power supplies for the clock drivers and the ADC
output driver to avoid modulating the clock signal with digital
noise. Low jitter, crystal controlled oscillators provide 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.
Refer to AN-501 Application Note, Aperture Uncertainty and ADC
System Performance, and AN-756 Application Note, Sampled
Systems and the Effects of Clock Phase Noise and Jitter, for more
information about jitter performance as it relates to ADCs.
Rev. B | Page 22 of 30
Data Sheet
AD9634
POWER DISSIPATION AND STANDBY MODE
As shown in Figure 57, the power dissipated by the AD9634 is
proportional to its sample rate. The data in Figure 57 was taken
using the same operating conditions as those used for the Typical
Performance Characteristics section.
0.4
0.25
0.20
DIGITAL OUTPUTS
0.15
0.2
IAVDD
0.10
SUPPLY CURRENT (A)
TOTAL POWER (W)
0.3
TOTAL POWER
The AD9634 output drivers can be configured for either ANSI
LVDS or reduced swing LVDS using a 1.8 V DRVDD supply.
As detailed in the AN-877 Application Note, Interfacing to High
Speed ADCs via SPI, the data format can be selected for offset
binary, twos complement, or gray code when using the SPI
control.
0.1
0.05
IDRVDD
40
55
70
0
85 100 115 130 145 160 175 190 205 220 235 250
ENCODE FREQUENCY (MSPS)
Digital Output Enable Function (OEB)
09996-053
0
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 when
faster wake-up times are required. To put the part into standby
mode, set the internal power-down mode bits (Bits[1:0]) in the
power modes register (Address 0x08) to 10. See the Memory
Map section and AN-877 Application Note, Interfacing to High
Speed ADCs via SPI for additional details.
Figure 57. AD9634-250 Power and Current vs. Sample Rate
By setting the internal power-down mode bits (Bits[1:0]) in the
power modes register (Address 0x08) to 01, the AD9634 is placed
in power-down mode. In this state, the ADC typically dissipates
5 mW. During power-down, the output drivers are placed in a
high impedance state.
Low power dissipation in power-down mode is achieved by
shutting down the reference, reference buffer, biasing networks,
and clock. Internal capacitors are discharged when entering powerdown mode and then must be recharged when returning to
normal operation. As a result, wake-up time is related to the
time spent in power-down mode, and shorter power-down
cycles result in proportionally shorter wake-up times.
The AD9634 has a flexible three-state ability for the digital output
pins. The three-state mode is enabled using the SPI interface.
The data outputs can be three-stated by using the output enable
bar bit (Bit 4) in Register 0x14. This OEB function is not intended
for rapid access to the data bus.
Timing
The AD9634 provides latched data with a pipeline delay of 10 input
sample clock cycles. Data outputs are available one propagation
delay (tPD) after the rising edge of the clock signal.
Minimize the length of the output data lines as well as the loads
placed on these lines to reduce transients within the AD9634.
These transients may degrade converter dynamic performance.
The lowest typical conversion rate of the AD9634 is 40 MSPS. At
clock rates below 40 MSPS, dynamic performance can degrade.
Data Clock Output (DCO)
The AD9634 also provides the data clock output (DCO) intended
for capturing the data in an external register. Figure 2 shows
timing diagram of the AD9634 output modes.
ADC OVERRANGE (OR)
The ADC overrange indicator is asserted when an overrange is
detected on the input of the ADC. The overrange condition is
determined at the output of the ADC pipeline and, therefore, is
subject to a latency of 10 ADC clock cycles. An overrange at the
input is indicated by this bit 10 clock cycles after it occurs.
Table 10. Output Data Format
Input (V)
VIN+ − VIN−
VIN+ − VIN−
VIN+ − VIN−
VIN+ − VIN−
VIN+ − VIN−
VIN+ − VIN−, Input Span = 1.75 V p-p (V)
< −0.875
= −0.875
=0
= +0.875
> +0.875
Offset Binary Output Mode
0000 0000 0000
0000 0000 0000
1000 0000 0000
1111 1111 1111
1111 1111 1111
Rev. B | Page 23 of 30
Twos Complement Mode (Default)
1000 0000 0000
1000 0000 0000
0000 0000 0000
0111 1111 1111
0111 1111 1111
OR
1
0
0
0
1
AD9634
Data Sheet
SERIAL PORT INTERFACE (SPI)
The AD9634 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 offers
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. These fields are documented in the
Memory Map section. For detailed operational information, see
the AN-877 Application Note, Interfacing to High Speed ADCs
via SPI.
CONFIGURATION USING THE SPI
Three pins define the SPI of this ADC: the SCLK pin, the SDIO
pin, and the CSB pin (see Table 11). The SCLK (serial clock) pin
is used to synchronize the read and write data presented from
and to the ADC. The SDIO (serial data input/output) pin is a
dual-purpose pin that allows data to be sent and read from the
internal ADC memory map registers. The CSB (chip select bar)
pin is an active-low control that enables or disables the read and
write cycles.
Table 11. Serial Port Interface Pins
Pin
SCLK
SDIO
CSB
Function
Serial clock. The serial shift clock input, which is used to
synchronize serial interface reads and writes.
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.
Chip select bar. An active-low control that 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. An example of the serial
timing and its definitions can be found in Figure 58 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 a high impedance mode. This mode turns
on any SPI pin secondary functions.
All data is composed of 8-bit words. The first bit of each individual
byte of serial data indicates whether a read or write command is
issued. This allows the serial data input/output (SDIO) pin to
change direction from an input to an output.
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. 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.
Data can be sent in MSB-first mode or in LSB-first mode. MSBfirst mode 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.
HARDWARE INTERFACE
The pins described in Table 11 comprise the physical interface
between the user programming device and the serial port of the
AD9634. 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.
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,
Microcontroller-Based Serial Port Interface (SPI) Boot Circuit.
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 AD9634 to prevent these signals from transitioning at the converter inputs during critical sampling periods.
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.
Rev. B | Page 24 of 30
Data Sheet
AD9634
SPI ACCESSIBLE FEATURES
Table 12. Features Accessible Using the SPI
Table 12 provides a brief description of the general features that
are accessible via the SPI. These features are described in detail in
AN-877 Application Note, Interfacing to High Speed ADCs via SPI.
Feature Name
Mode
Clock
Offset
Test I/O
Output Mode
Output Phase
Output Delay
VREF
Digital
Processing
tHIGH
tDS
tS
tDH
Description
Allows the user to set either power-down mode
or standby mode
Allows the user to access the DCS via the SPI
Allows the user to digitally adjust the
converter offset
Allows the user to set test modes to have
known data on output bits
Allows the user to set up outputs
Allows the user to set the output clock polarity
Allows the user to vary the DCO delay
Allows the user to set the reference voltage
Allows the user to enable the synchronization
features
tCLK
tH
tLOW
CSB
SDIO DON’T CARE
DON’T CARE
R/W
W1
W0
A12
A11
A10
A9
A8
A7
D5
Figure 58. Serial Port Interface Timing Diagram
Rev. B | Page 25 of 30
D4
D3
D2
D1
D0
DON’T CARE
09996-055
SCLK DON’T CARE
AD9634
Data Sheet
MEMORY MAP
READING THE MEMORY MAP REGISTER TABLE
Default Values
Each row in the memory map register table has eight bit
locations. The memory map is roughly divided into three
sections: the chip configuration registers (Address 0x00 to
Address 0x02), the transfer register (Address 0xFF), and the
ADC functions registers (Address 0x08 to Address 0x20),
including setup, control, and test.
After the AD9634 is reset, critical registers are loaded with
default values. The default values for the registers are given in
the memory map register table (see Table 13).
Logic Levels
An explanation of logic level terminology follows:
The memory map register table (Table 13) documents the
default hexadecimal value for each hexadecimal address shown.
The Bit 7 (MSB) column is the start of the default hexadecimal
value given. For example, Address 0x14, the output mode register,
has a hexadecimal default value of 0x01. This means that Bit 0 = 1
and the remaining bits are 0s. This setting is the default output
format value, which is twos complement. For more information
on this function and others, see the AN-877 Application Note,
Interfacing to High Speed ADCs via SPI. This document details
the functions controlled by Register 0x00 to Register 0x20.
Open Locations
•
•
“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 to Address 0x20 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 then the bit autoclears.
All address and bit locations that are not included in Table 13
are not currently supported for this device. Write 0s to unused
bits of a valid address location. 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), do not write to this address location.
Rev. B | Page 26 of 30
Data Sheet
AD9634
MEMORY MAP REGISTER TABLE
All address and bit locations that are not included in Table 13 are not currently supported for this device.
Table 13. Memory Map Registers
Addr
Register
Bit 7
(Hex)
Name
(MSB)
Chip Configuration Registers
0x00
SPI port
0
configuration
0x01
0x02
Chip ID
Chip grade
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
LSB first
Soft reset
1
1
Soft reset
LSB first
0
Open
Open
Open
Transfer
8-bit chip ID[7:0], AD9634 = 0x87 (default)
Speed grade ID;
Open
Open
00 = 250 MSPS
01 = 210 MSPS
11 = 170 MSPS
Open
Open
Transfer Register
0xFF
Transfer
Open
Open
Open
Open
Open
Open
ADC Function Registers
0x08
Power modes
Open
Open
Open
Open
Open
Open
0x09
Global clock
Open
Open
Open
Open
Open
Open
0x0B
Clock divide
Open
Open
0x0D
Test mode
Test mode
0 = continuous/
repeat
pattern
1 = single
pattern
then zeros
Open
0x10
Offset adjust
Open
Open
Input clock divider phase adjust
000 = no delay
001 = 1 input clock cycle
010 = 2 input clock cycles
011 = 3 input clock cycles
100 = 4 input clock cycles
101 = 5 input clock cycles
110 = 6 input clock cycles
111 = 7 input clock cycles
Reset PN
long gen
Reset PN
short gen
Default
Notes/
Comments
0x18
Nibbles are
mirrored so
that LSBfirst mode
or MSB-first
mode is set
correctly,
regardless
of shift
mode.
Read only.
Speed
grade ID
used to
differentiate
devices;
read only.
0x87
Internal power-down mode
00 = normal operation
01 = full power-down
10 = standby
11 = reserved
Open
Duty cycle
stabilizer
(default)
Clock divide ratio
000 = divide by 1
001 = divide by 2
010 = divide by 3
011 = divide by 4
100 = divide by 5
101 = divide by 6
110 = divide by 7
111 = divide by 8
Output test mode
0000 = off (default)
0001 = midscale short
0010 = positive FS
0011 = negative FS
0100 = alternating checkerboard
0101 = PN long sequence
0110 = PN short sequence
0111 = one/zero word toggle
1000 = user test mode
1001 to 1110 = unused
1111 = ramp output
Offset adjust in LSBs from +31 to −32
(twos complement format)
Rev. B | Page 27 of 30
Default
Value
(Hex)
0x00
Synchronously
transfers
data from
the master
shift
register to
the slave.
0x00
Determines
various
generic
modes of
chip
operation.
0x01
0x00
0x00
0x00
Clock divide
values other
than 000
automatically
cause the
duty cycle
stabilizer to
become
active.
When this
register is
set, the test
data is
placed on
the output
pins in
place of
normal
data.
AD9634
Data Sheet
Addr
(Hex)
0x14
Register
Name
Output mode
Bit 7
(MSB)
Open
Bit 6
Open
Bit 5
Open
Bit 4
Output
enable bar
0 = on
(default)
1 = off
Bit 3
Open
0x15
Output adjust
Open
Open
Open
Open
0x16
Clock phase
control
DCO output
delay
Invert
DCO clock
Enable
DCO
clock
delay
Open
Open
Open
LVDS output drive current adjust
0000 = 3.72 mA output drive current
0001 = 3.5 mA output drive current (default)
0010 = 3.30 mA output drive current
0011 = 2.96 mA output drive current
0100 = 2.82 mA output drive current
0101 = 2.57 mA output drive current
0110 = 2.27 mA output drive current
0111 = 2.0 mA output drive current (reduced range)
1000 to 1111 = reserved
Open
Open
Open
Open
Open
Open
0x18
Input span
select
Open
0x19
User Test
Pattern 1 LSB
User Test
Pattern 1 MSB
User Test
Pattern 2 LSB
User Test
Pattern 2 MSB
User Test
Pattern 3 LSB
User Test
Pattern 3 MSB
User Test
Pattern 4 LSB
User Test
Pattern 4 MSB
0x17
0x1A
0x1B
0x1C
0x1D
0x1E
0x1F
0x20
Open
Open
Bit 2
Output
invert
0 = normal
(default)
1=
inverted
Bit 0
Bit 1
(LSB)
Output format
00 = offset binary
01 = twos complement
(default)
10 = gray code
11 = reserved
Default
Value
(Hex)
0x01
0x01
0x00
DCO clock delay
[delay = (3100 ps × register value/31 + 100)]
00000 = 100 ps
00001 = 200 ps
00010 = 300 ps
…
11110 = 3100 ps
11111 = 3200 ps
Full-scale input voltage selection
01111 = 2.087 V p-p
…
00001 = 1.772 V p-p
00000 = 1.75 V p-p (default)
11111 = 1.727 V p-p
…
10000 = 1.383 V p-p
User Test Pattern 1[7:0]
0x00
User Test Pattern 1[15:8]
0x00
User Test Pattern 2[7:0]
0x00
User Test Pattern 2[15:8]
0x00
User Test Pattern 3[7:0]
0x00
User Test Pattern 3[15:8]
0x00
User Test Pattern 4[7:0]
0x00
User Test Pattern 4[15:8]
0x00
Rev. B | Page 28 of 30
Default
Notes/
Comments
Configures
the outputs
and the
format of
the data.
0x00
0x00
Full-scale
input
adjustment
in 0.022 V
steps.
Data Sheet
AD9634
APPLICATIONS INFORMATION
DESIGN GUIDELINES
Before starting system-level design and layout of the AD9634, it
is recommended that the designer become familiar with these
guidelines, which describe the special circuit connections and
layout requirements needed for certain pins.
Power and Ground Recommendations
When connecting power to the AD9634, it is recommended that
two separate 1.8 V supplies be used: use one supply for analog
(AVDD) and a separate supply for digital outputs (DRVDD).
The designer can employ several different decoupling capacitors
to cover both high and low frequencies. Locate these capacitors
close to the point of entry at the PC board level and close to the
pins of the part with minimal trace length.
A single PCB ground plane should be sufficient when using the
AD9634. With proper decoupling and smart partitioning of the
PCB analog, digital, and clock sections, optimum performance
can be easily achieved.
Exposed Paddle Thermal Heat Slug Recommendations
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 be connected
to the AD9634 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 filled or plugged with
nonconductive epoxy.
To maximize the coverage and adhesion between the ADC and
the PCB, overlay a silkscreen to partition the 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. See the evaluation
board for a PCB layout example. For detailed information about
the packaging and PCB layout of chip scale packages, refer to
the AN-772 Application Note, A Design and Manufacturing
Guide for the Lead Frame Chip Scale Package (LFCSP).
VCM
Decouple the VCM pin to ground with a 0.1 µF capacitor, as
shown in Figure 48.
SPI Port
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
AD9634 to keep these signals from transitioning at the converter
input pins during critical sampling periods.
Rev. B | Page 29 of 30
AD9634
Data Sheet
OUTLINE DIMENSIONS
0.30
0.25
0.18
32
25
1
24
0.50
BSC
*3.75
3.60 SQ
3.55
EXPOSED
PAD
17
TOP VIEW
0.80
0.75
0.70
0.50
0.40
0.30
8
16
0.05 MAX
0.02 NOM
COPLANARITY
0.08
0.20 REF
SEATING
PLANE
PIN 1
INDICATOR
9
BOTTOM VIEW
0.25 MIN
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-WHHD-5
WITH THE EXCEPTION OF THE EXPOSED PAD DIMENSION.
08-16-2010-B
PIN 1
INDICATOR
5.10
5.00 SQ
4.90
Figure 59. 32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
5 mm × 5 mm Body, Very Very Thin Quad
(CP-32-12)
Dimensions shown in millimeters
ORDERING GUIDE
Model1
AD9634BCPZ-250
AD9634BCPZRL7-250
AD9634BCPZ-210
AD9634BCPZRL7-210
AD9634BCPZ-170
AD9634BCPZRL7-170
AD9634-170EBZ
AD9634-210EBZ
AD9634-250EBZ
1
Temperature Range
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
Package Description
32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
Evaluation Board with AD9634 and Software
Evaluation Board with AD9634 and Software
Evaluation Board with AD9634 and Software
Z = RoHS Compliant Part.
©2011–2014 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D09996-0-12/14(B)
Rev. B | Page 30 of 30
Package Option
CP-32-12
CP-32-12
CP-32-12
CP-32-12
CP-32-12
CP-32-12
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