Analog Devices AD9236 Service Manual

12-Bit, 80 MSPS, 3 V A/D Converter

FEATURES

Single 3 V supply operation (2.7 V to 3.6 V) SNR = 70.4 dBc to Nyquist SFDR = 87.8 dBc to Nyquist Low power: 366 mW Differential input with 500 MHz bandwidth On-chip reference and sample-and-hold DNL = ±0.4 LSB Flexible analog input: 1 V p-p to 2 V p-p range Offset binary or twos complement data format Clock duty cycle stabilizer

APPLICATIONS

High end medical imaging equipment IF sampling in communications receivers
WCDMA, CDMA-One, CDMA-2000 Battery-powered instruments Hand-held scopemeters Low cost digital oscilloscopes DTV subsystems

GENERAL DESCRIPTION

The AD9236 is a monolithic, single 3 V supply, 12-bit, 80 MSPS analog-to-digital converter featuring a high performance sample­and-hold amplifier (SHA) and voltage reference. The AD9236 uses a multistage differential pipelined architecture with output error correction logic to provide 12-bit accuracy at 80 MSPS and guarantee no missing codes over the full operating temperature range.
The wide bandwidth, truly differential SHA allows a variety of user-selectable input ranges and common modes, including single-ended applications. It is suitable for multiplexed systems that switch full-scale voltage levels in successive channels and for sampling single-channel inputs at frequencies well beyond the Nyquist rate. Combined with power and cost savings over previously available analog-to-digital converters, the AD9236 is suitable for applications in communications, imaging, and medical ultrasound.
A single-ended clock input is used to control all internal conversion cycles. A duty cycle stabilizer (DCS) compensates for wide variations in the clock duty cycle while maintaining excellent overall ADC performance. The digital output data is
AD9236

FUNCTIONAL BLOCK DIAGRAM

DRVDDAVDD
AD9236
VIN+ VIN–
REFT REFB
VREF
SENSE
SHA
REF
SELECT
A/D
AGND
MDAC1
4
0.5V
presented in straight binary or twos complement formats. An out-of-range (OTR) signal indicates an overflow condition that can be used with the most significant bit to determine low or high overflow. Fabricated on an advanced CMOS process, the AD9236 is available in a 28-lead TSSOP and a 32-lead LFCSP and is specified over the industrial temperature range (−40°C to +85°C).

PRODUCT HIGHLIGHTS

1. The AD9236 operates from a single 3 V power supply and
features a separate digital output driver supply to accommodate 2.5 V and 3.3 V logic families.
2. Operating at 80 MSPS, the AD9236 consumes a low 366 mW.
3. The patented SHA input maintains excellent performance for
input frequencies up to 100 MHz, and can be configured for single-ended or differential operation.
4. The AD9236 is pin compatible with the AD9215, AD9235,
and AD9245. This allows a simplified migration from 10 bits to 14 bits and 20 MSPS to 80 MSPS.
5. The DCS maintains overall ADC performance over a wide
range of clock pulse widths.
6. The OTR output bit indicates when the signal is beyond the
selected input range.
8-STAGE
1 1/2-BIT PIPELINE
16
CORRECTION LOGIC
12
OUTPUT BUFFERS
CLOCK
DUTY CYCLE
STABILIZER
CLK PDWN MODE DGND
Figure 1.
MODE
SELECT
A/D
3
OTR
D11 (MSB) D0 (LSB)
03066-0-001
Rev. B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 © 2006 Analog Devices, Inc. All rights reserved.
AD9236

TABLE OF CONTENTS

Features .............................................................................................. 1
Equivalent Circuits......................................................................... 10
Applications....................................................................................... 1
General Description......................................................................... 1
Functional Block Diagram .............................................................. 1
Product Highlights........................................................................... 1
Revision History ............................................................................... 2
DC Specifications ............................................................................. 3
AC Specifications.............................................................................. 4
Digital Specifications........................................................................ 5
Switching Specifications .................................................................. 6
Absolute Maximum Ratings............................................................ 7
Thermal Resistance ...................................................................... 7
ESD Caution.................................................................................. 7
Te r mi n ol o g y ...................................................................................... 8
Pin Configurations and Function Descriptions ........................... 9
Typical Perf or m an c e Charac t e r istics ........................................... 11
Theory of Operation ...................................................................... 14
Analog Input and Reference Overview ................................... 14
Clock Input Considerations...................................................... 15
Power Dissipation and Standby Mode .................................... 16
Digital Outputs........................................................................... 16
Timing ......................................................................................... 17
Volt a ge R e fer e nce ....................................................................... 17
Operational Mode Selection ..................................................... 18
Evaluation Board ........................................................................ 18
Outline Dimensions ....................................................................... 33
Ordering Guide .......................................................................... 34

REVISION HISTORY

1/06—Rev. A to Rev. B
Changes to Figure 29...................................................................... 15
Changes to Equation in Jitter Considerations Section ..............16
Changes to Internal Reference Connection Section, Figure 34,
and Table 10..................................................................................... 17
Changes to Figure 35...................................................................... 18
Changes to Figure 38...................................................................... 20
Changes to Figure 39...................................................................... 21
Changes to Figure 48...................................................................... 27
Changes to Figure 49...................................................................... 28
Changes to Figure 50...................................................................... 29
Changes to Table 12........................................................................ 32
Updated Outline Dimensions....................................................... 33
Changes to Ordering Guide.......................................................... 34
10/03—Rev. 0 to Rev. A
Changes to Figure 30...................................................................... 15
Changes to Figure 33 ..................................................................... 17
Changes to Figure 40...................................................................... 22
Changes to Figure 49...................................................................... 28
Changes to Figure 50...................................................................... 29
Changes to Table 11 ....................................................................... 32
Changes to Ordering Guide ......................................................... 33
Rev. B | Page 2 of 36
AD9236

DC SPECIFICATIONS

AVDD = 3 V, DRVDD = 2.5 V, sample rate = 80 MSPS, 2 V p-p differential input, 1.0 V external reference, unless otherwise noted.
Table 1.
AD9236BRU/AD9236BCP
Parameter Temp Test Level
Min Typ Max
RESOLUTION Full VI 12 Bits ACCURACY
No Missing Codes Full VI Guaranteed Offset Error
1
Full VI ±0.30 ±1.30 % FSR Gain Error 25°C V ±0.10 % FSR Gain Error Differential Nonlinearity (DNL) Integral Nonlinearity (INL)
1
2
2
Full VI ±0.30 ±4.34 % FSR
Full VI ±0.40 ±0.65 LSB
Full VI ±0.35 ±1.20 LSB
TEMPERATURE DRIFT
Offset Error
1
Full V ±6 ppm/°C Gain Error Full V ±12 ppm/°C Gain Error
1
Full V ±18 ppm/°C
INTERNAL VOLTAGE REFERENCE
Output Voltage Error (1 V) Full VI ±2 ±35 mV Load Regulation @ 1.0 mA 25°C V 0.8 mV Output Voltage Error (0.5 V) 25°C V ±1 mV Load Regulation @ 0.5 mA 25°C V 0.1 mV
INPUT REFERRED NOISE
VREF = 0.5 V 25°C V 0.55 LSB rms VREF = 1.0 V 25°C V 0.28 LSB rms
ANALOG INPUT
Input Span, VREF = 0.5 V Full IV 1 V p-p Input Span, VREF = 1.0 V Full IV 2 V p-p Input Capacitance
3
Full V 7 pF
REFERENCE INPUT RESISTANCE Full V 7 kΩ POWER SUPPLIES
Supply Voltage
AVDD Full IV 2.7 3.0 3.6 V DRVDD Full IV 2.25 2.5 3.6 V
Supply Current
4
IAVDD IDRVDD
4
Full VI 122 137 mA
25°C V 8 mA PSRR 25°C V ±0.01 % FSR
POWER CONSUMPTION
Low Frequency Input Standby Power
1
With a 1.0 V internal reference.
2
Measured at low input frequency, full-scale sine wave, with approximately 5 pF loading on each output bit.
3
Input capacitance refers to the effective capacitance between one differential input pin and AGND. Refer to Figure 5 for the equivalent analog input structure.
4
Measured at AC Specifications conditions without output drivers.
5
Measured with a dc input, CLK pin inactive (that is, set to AVDD or AGND).
4
5
25°C V 366 mW
25°C V 1.0 mW
Unit
Rev. B | Page 3 of 36
AD9236

AC SPECIFICATIONS

AVDD = 3 V, DRVDD = 2.5 V, sample rate = 80 MSPS, 2 V p-p differential input, 1.0 V external reference, AIN = –0.5 dBFS, DCS off, unless otherwise noted.
Table 2.
AD9236BRU/AD9236BCP
Parameter Temp Test Level
SIGNAL-TO-NOISE-RATIO (SNR)
fIN = 2.4 MHz Full VI 68.6 dB
25°C V 70.9 dB
fIN = 40 MHz 25°C V 70.4 dB fIN = 70 MHz Full IV 67.8 dB
25°C V 70.1 dB
fIN = 100 MHz 25°C V 69.0 dB
SIGNAL-TO-NOISE AND DISTORTION (SINAD)
fIN = 2.4 MHz Full VI 68.4 dB
25°C V 70.8 dB
fIN = 40 MHz 25°C V 70.2 dB fIN = 70 MHz Full IV 67.4 dB
25°C V 69.8 dB
fIN = 100 MHz 25°C V 68.0 dB
EFFECTIVE NUMBER OF BITS (ENOB)
fIN = 2.4 MHz Full VI 11.1 Bits
25°C V 11.5 Bits
fIN = 40 MHz 25°C V 11.4 Bits fIN = 70 MHz Full IV 10.9 Bits
25°C V 11.3 Bits
fIN = 100 MHz 25°C V 11.0 Bits
WORST SECOND OR THIRD
fIN = 2.4 MHz Full VI –75.6 dBc 25°C V –91.3 dBc fIN = 40 MHz 25°C V –87.8 dBc fIN = 70 MHz Full VI –73.2 dBc 25°C V –81.4 dBc fIN = 100 MHz 25°C V –76.4 dBc
SPURIOUS FREE DYNAMIC RANGE (SFDR)
fIN = 2.4 MHz Full VI 75.6 dBc
25°C V 91.3 dBc
fIN = 40 MHz 25°C V 87.8 dBc fIN = 70 MHz Full IV 73.2 dBc
25°C V 81.4 dBc
fIN = 100 MHz 25°C V 76.4 dBc
Min Typ Max
Unit
Rev. B | Page 4 of 36
AD9236

DIGITAL SPECIFICATIONS

AVDD = 3 V, DRVDD = 2.5 V, 1.0 V external reference, unless otherwise noted.
Table 3.
AD9236BRU/AD9236BCP
Parameter Temp Test Level
LOGIC INPUTS (CLK, PDWN)
High Level Input Voltage Full IV 2.0 V Low Level Input Voltage Full IV 0.8 V High Level Input Current Full IV –10 +10 μA Low Level Input Current Full IV –10 +10 μA Input Capacitance Full V 2 pF
DIGITAL OUTPUTS (D0–D11, OTR)
DRVDD = 3.3 V
High Level Output Voltage (IOH = 50 μA) Full IV 3.29 V High Level Output Voltage (IOH = 0.5 mA) Full IV 3.25 V Low Level Output Voltage (IOH = 1.6 mA) Full IV 0.2 V Low Level Output Voltage (IOH = 50 μA) Full IV 0.05 V
DRVDD = 2.5 V
High Level Output Voltage (IOH = 50 μA) Full IV 2.49 V High Level Output Voltage (IOH = 0.5 mA) Full IV 2.45 V Low Level Output Voltage (IOH = 1.6 mA) Full IV 0.2 V Low Level Output Voltage (IOH = 50 μA) Full IV 0.05 V
1
Output voltage levels measured with 5 pF load on each output.
1
Min Typ Max
Unit
Rev. B | Page 5 of 36
AD9236

SWITCHING SPECIFICATIONS

AVDD = 3 V, DRVDD = 2.5 V, unless otherwise noted.
Table 4.
AD9236BRU/AD9236BCP
Parameter Temp Test Level
Min Typ Max
CLOCK INPUT PARAMETERS
Maximum Conversion Rate Full VI 80 MSPS Minimum Conversion Rate Full V 1 MSPS CLK Period Full V 12.5 ns CLK Pulse Width High CLK Pulse Width Low
1
1
Full V 4.0 ns Full V 4.0 ns
DATA OUTPUT PARAMETERS
Output Propagation Delay (tPD)
2
Full V 3.5 ns Pipeline Delay (Latency) Full V 7 Cycles Aperture Delay (tA) Full V 1.0 ns Aperture Uncertainty (Jitter, tJ) Full V 0.3 ps rms Wake-Up Time
3
Full V 7 ms
OUT OF RANGE RECOVERY TIME Full V 2 Cycles
1
With duty cycle stabilizer (DCS) enabled.
2
Output propagation delay is measured from CLK 50% transition to DATA 50% transition, with 5 pF load.
3
Wake-up time is dependant on the value of the decoupling capacitors; typical values shown with 0.1 μF and 10 μF capacitors on REFT and REFB.
Unit
N+1
ANALOG
INPUT
CLK
DATA
OUT
N
N–1
N–9 N–8 N–7 N–6 N–5 N–4 N–3 N–2 N–1 N
t
N+2
A
N+3
Figure 2. Timing Diagram
N+4
N+5
t
= 6.0ns MAX
PD
2.0ns MIN
N+6
N+7
N+8
03066-0-002
Table 5. Explanation of Test Levels
Test Level Definitions
I 100% production tested. II 100% production tested at 25°C and guaranteed by design and characterization at specified temperatures. III Sample tested only. IV Parameter is guaranteed by design and characterization testing. V Parameter is a typical value only. VI 100% production tested at 25°C and guaranteed by design and characterization for industrial temperature range.
Rev. B | Page 6 of 36
AD9236

ABSOLUTE MAXIMUM RATINGS

Table 6.
With
Parameter Min Max Unit ELECTRICAL
AVDD AGND –0.3 +3.9 DRVDD DGND –0.3 +3.9 V AGND DGND –0.3 +0.3 V AVDD DRVDD –3.9 +3.9 V D0 to D11 DGND –0.3 DRVDD + 0.3 V CLK, MODE AGND –0.3 AVDD + 0.3 V VIN+, VIN– AGND –0.3 AVDD + 0.3 VREF AGND –0.3 AVDD + 0.3 V SENSE AGND –0.3 AVDD + 0.3 V REFT, REFB AGND –0.3 AVDD + 0.3 V PDWN AGND –0.3 AVDD + 0.3 V
ENVIRONMENTAL
Storage Temperature –65 +125 °C Operating Temperature Range –40 +85 °C Lead Temperature
(Soldering 10 sec)
Junction Temperature 150 °C
Respect to
V
V
300 °C
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and 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.

THERMAL RESISTANCE

θ
is specified for the worst-case conditions on a 4-layer board
JA
in still air, in accordance with EIA/JESD51-1.
Table 7.
Package Type Unit
RU-28 67.7 °C/W CP-32-2 32.5 32.71 °C/W
θ
JA JC
Airflow increases heat dissipation effectively, reducing θ addition, more metal directly in contact with the package leads from metal traces, through holes, ground, and power planes reduces the θ
. It is recommended that the exposed paddle be
JA
soldered to the ground plane for the LFCSP package. There is an increased reliability of the solder joints, and maximum thermal capability of the package is achieved with the exposed paddle soldered to the customer board.
θ
. In
JA

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
Rev. B | Page 7 of 36
AD9236
(

TERMINOLOGY

Analog Bandwidth (Full Power Bandwidth)
The analog input frequency at which the spectral power of the fundamental frequency (as determined by the FFT analysis) is reduced by 3 dB.
Signal-to-Noise and Distortion (SINAD)
The ratio of the rms input signal amplitude to the rms value of the sum of all other spectral components below the Nyquist frequency, including harmonics but excluding dc.
1
Aperture Delay (t
)
A
The delay between the 50% point of the rising edge of the clock and the instant at which the analog input is sampled.
Aperture Uncertainty (Jitter, t
)
J
The sample-to-sample variation in aperture delay.
Integral Nonlinearity (INL)
The deviation of each individual code from a line drawn from negative full scale through positive full scale. The point used as negative full scale occurs ½ LSB before the first code transition. Positive full scale is defined as a level 1½ LSB beyond the last code transition. The deviation is measured from the middle of each particular code to the true straight line.
Differential Nonlinearity (DNL, No Missing Codes)
An ideal ADC exhibits code transitions that are exactly 1 LSB apart. DNL is the deviation from this ideal value. Guaranteed no missing codes to 12-bit resolution indicates that all 4096 codes must be present over all operating ranges.
Offset Error
The major carry transition should occur for an analog value ½ LSB below VIN+ = VIN–. Offset error is defined as the deviation of the actual transition from that point.
Gain Error
The first code transition should occur at an analog value ½ LSB above negative full scale. The last transition should occur at an analog value 1½ LSB below positive full scale. Gain error is the deviation of the actual difference between first and last code transitions and the ideal difference between first and last code transitions.
Tem p er at u re Dr i ft
The temperature drift for offset error and gain error specifies the maximum change from the initial (25°C) value to the value at T
MIN
or T
MAX
.
Power Supply Rejection Ratio
The change in full scale from the value with the supply at the minimum limit to the value with the supply at its maximum limit.
Total Harmonic Distortion (THD)
1
The ratio of the rms input signal amplitude to the rms value of the sum of the first six harmonic components.
Effective Number of Bits (ENOB)
The effective number of bits for a sine wave input at a given input frequency can be calculated directly from its measured
SINAD using the following formula
SINAD
=
ENOB
Signal-to-Noise Ratio (SNR)
)
76.1
02.6
1
The ratio of the rms input signal amplitude to the rms value of the sum of all other spectral components below the Nyquist frequency, excluding the first six harmonics and dc.
Spurious Free Dynamic Range (SFDR)
1
The difference in dB between the rms input signal amplitude and the peak spurious signal. The peak spurious component may or may not be a harmonic.
Two -Tone SFDR
1
The ratio of the rms value of either input tone to the rms value of the peak spurious component. The peak spurious component may or may not be an IMD product.
Clock Pulse Width and Duty Cycle
Pulse width high is the minimum amount of time that the clock pulse should be left in the Logic 1 state to achieve rated performance. Pulse width low is the minimum time the clock pulse should be left in the low state. At a given clock rate, these specifications define an acceptable clock duty cycle.
Minimum Conversion Rate
The clock rate at which the SNR of the lowest analog signal frequency drops by no more than 3 dB below the guaranteed limit.
Maximum Conversion Rate
The clock rate at which parametric testing is performed.
Output Propagation Delay (t
)
PD
The delay between the clock rising edge and the time when all bits are within valid logic levels.
Out-of-Range Recovery Time
The time it takes for the ADC to reacquire the analog input after a transition from 10% above positive full scale to 10% above negative full scale, or from 10% below negative full scale to 10% below positive full scale.
1
AC specifications may be reported in dBc (degrades as signal levels are
lowered) or in dBFS (always related back to converter full scale).
Rev. B | Page 8 of 36
AD9236

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

OTR 1
MODE 2
SENSE 3
VREF 4 REFB 5 REFT 6
AVDD 7
AGND 8
VIN+ 9 VIN– 10
AGND 11
AVDD 12
CLK 13
PDWN 14
AD9236
TOP VIEW
(Not to Scale)
03066-0-021
Figure 3. 28-Lead TSSOP
Table 8. Pin Function Descriptions—28-Lead TSSOP
D11 (MSB)28 D1027 D926 D825 DRVDD24 DGND23 D722 D621 D520 D419 D318 D217 D116 D0 (LSB)15
DNC 1 CLK 2 DNC 3
PDWN 4
DNC 5 DNC 6
(LSB) D0 7
D1 8
32 AVDD
31 AGND
(Not to Scale)
D2 9
D3 10
30 VIN–
29 VIN+
AD9236
CSP
TOP VIEW
D4 11
D5 12
28 AGND
27 AVDD
D6 13
D7 14
26 REFT
DGND 15
25 REFB
24 VREF 23 SENSE 22 MODE 21 OTR 20 D11 (MSB) 19 D10 18 D9 17 D8
DRVDD 16
Figure 4. 32-Lead LFCSP
Table 9. Pin Function Descriptions—32-Lead LFCSP
Pin No. Mnemonic Description Pin No. Mnemonic Description
1 OTR Out-of-Range Indicator 1, 3, 5, 6 DNC Do Not Connect 2 MODE
Data Format Select and DCS
Mode Selection 3 SENSE Reference Mode Selection 4 VREF Voltage Reference Input/Output 5 REFB Differential Reference (–) 6 REFT Differential Reference (+) 7, 12 AVDD Analog Power Supply 8, 11 AGND Analog Ground 9 VIN+ Analog Input Pin (+) 10 VIN– Analog Input Pin (–) 13 CLK Clock Input Pin 14 PDWN Power-Down Function Select 15 to 22,
25 to 28
D0 (LSB) to D11 (MSB)
Data Output Bits
23 DGND Digital Output Ground 24 DRVDD Digital Output Driver Supply
2 CLK Clock Input Pin 4 PDWN Power-Down Function Select 7 to 14,
17 to 20
D0 (LSB) to D11 (MSB)
Data Output Bits
15 DGND Digital Output Ground 16 DRVDD Digital Output Driver Supply 21 OTR Out-of-Range Indicator 22 MODE
Data Format Select and DCS
Mode Selection 23 SENSE Reference Mode Selection 24 VREF Voltage Reference Input/Output 25 REFB Differential Reference (–) 26 REFT Differential Reference (+) 27, 32 AVDD Analog Power Supply 28, 31 AGND Analog Ground 29 VIN+ Analog Input Pin (+) 30 VIN– Analog Input Pin (–)
03066-0-022
Rev. B | Page 9 of 36
AD9236
V

EQUIVALENT CIRCUITS

AVDD
DRVDD
IN+, VIN–
03600-0-003
Figure 5. Equivalent Analog Input Circuit
AVDD
MODE
20kΩ
03600-0-004
Figure 6. Equivalent MODE Input Circuit
D11-D0, OTR
03600-0-005
Figure 7. Equivalent Digital Output Circuit
AVDD
CLK,
PDWN
03600-0-006
Figure 8. Equivalent Digital Input Circuit
Rev. B | Page 10 of 36
AD9236

TYPICAL PERFORMANCE CHARACTERISTICS

AVDD = 3.0 V, DRVDD = 2.5 V, sample rate = 80 MSPS, DCS disabled, TA = 25°C, 2 V p-p differential input, AIN = –0.5 dBFS, VREF = 1.0 V external, unless otherwise noted.
0 –10 –20 –30 –40 –50 –60 –70 –80
AMPLITUDE (dBFS)
–90
–100 –110 –120
0 5 10 15 20 25 30 35 40
FREQUENCY (MHz)
AIN = –0.5dBFS SNR = 71.0dBc ENOB = 11.5 BITS SFDR = 93.6dBc
Figure 9. Single Tone 8K FFT @ 2.5 MHz
03066-0-031
100
90
80
70
60
SNR/SFDR (dBc AND dBFS)
50
40
–30 –25 –20 –15 –10 –5 0
SFDR (dBFS)
SFDR (dBc)
SNR (dBFS)
SNR (dBc)
INPUT AMPLITUDE (dBFS)
SFDR = 90dB
REFERENCE LINE
03066-0-048
Figure 12. Single Tone SNR/SFDR vs. Input Amplitude (AIN) @ 2.5 MHz
0
AIN = –0.5dBFS SNR = 70.6dBc
–10
ENOB = 11.4 BITS SFDR = 87.8dBc
–20 –30 –40 –50 –60 –70 –80
AMPLITUDE (dBFS)
–90
–100 –110 –120
0 5 10 15 20 25 30 35 40
FREQUENCY (MHz)
Figure 10. Single Tone 8K FFT @ 39 MHz
0 –10 –20 –30 –40 –50 –60 –70 –80
AMPLITUDE (dBFS)
–90
–100 –110 –120
0 5 10 15 20 25 30 35 40
FREQUENCY (MHz)
AIN = –0.5dBFS SNR = 70.1dBc ENOB = 11.3 BITS SFDR = 81.9dBc
Figure 11. Single Tone 8K FFT @ 70 MHz Figure 14. SNR/SFDR vs. Sample Rate @ 10 MHz
100
90
80
70
60
SNR/SFDR (dBc AND dBFS)
50
40
–30 –25 –20 –15 –10 –5 0
03066-0-032
SFDR (dBFS)
SFDR (dBc)
REFERENCE LINE
SNR (dBFS)
INPUT AMPLITUDE (dBFS)
Figure 13. Single Tone SNR/SFDR vs. Input Amplitude (AIN) @ 39 MHz
100
SFDR (DIFF)
90
SFDR (SE)
80
70
SNR/SFDR (dBc)
60
50
04020 60
03066-0-033
SAMPLE RATE (MSPS)
SFDR = 90dB
SNR (dBc)
03066-0-049
SNR (DIFF)
SNR (SE)
80 100
03066-0-042
Rev. B | Page 11 of 36
AD9236
0
AIN = –6.5dBFS SNR = 71.3dBFS
–10
SFDR = 92.5dBc
–20 –30 –40 –50 –60 –70 –80
AMPLITUDE (dBFS)
–90 –100 –110 –120
0 5 10 15 20 25 30 35 40
FREQUENCY (MHz)
Figure 15. Two-Tone 8K FFT @ 30 MHz and 31 MHz
03066-0-036
100
90
80
70
60
SNR/SFDR (dBc AND dBFS)
50
40
–30 –27 –24 –21 –18 –15 –12 –9 –6
SFDR = 90dB
REFERENCE LINE
Figure 18. Two-Tone SNR/SFDR vs. Input Amplitude @ 30 MHz and 31 MHz
SFDR (dBFS)
SFDR (dBc)
SNR (dBFS)
INPUT AMPLITUDE (dBFS)
SNR (dBc)
03066-0-039
0 –10 –20 –30 –40 –50 –60 –70 –80
AMPLITUDE (dBFS)
–90
–100 –110 –120
0 5 10 15 20 25 30 35 40
FREQUENCY (MHz)
AIN = –6.5dBFS SNR = 71.0dBFS SFDR = 79.3dBc
Figure 16. Two-Tone 8K FFT @ 69 MHz and 70 MHz
1.0
0.8
0.6
0.4
0.2
0
INL (LSB)
–0.2
–0.4
–0.6
–0.8
–1.0
0 1024 2048 3072 4096
CODE
Figure 17. Typical INL Figure 20. Typical DNL
100
90
80
70
60
SNR/SFDR (dBc AND dBFS)
50
40
–30 –27 –24 –21 –18 –15 –12 –9 –6
03066-0-037
SFDR (dBc)
SFDR = 90dB REFERENCE LINE
SFDR (dBFS)
SNR (dBFS)
INPUT AMPLITUDE (dBFS)
Figure 19. Two-Tone SNR/SFDR vs. Input Amplitude @ 69 MHz and 70 MHz
1.0
0.8
0.6
0.4
0.2
0
DNL (LSB)
–0.2
–0.4
–0.6
–0.8
–1.0
03066-0-038
0 1024 2048 3072 4096
CODE
SNR(dBc)
03066-0-040
03066-0-041
Rev. B | Page 12 of 36
AD9236
72.0
100
71.5
71.0
70.5
70.0
SNR (dBc)
69.5
69.0
68.5
68.0 0 25 50 75 100 125
INPUT FREQUENCY (MHz)
Figure 21. SNR vs. Input Frequency
95
SFDR (DCS ON)
90
85
80
75
70
SNR/SFDR (dBc)
65
60
55
30 35 40 45 50 55 60 65 70
SNR (DCS OFF)
DUTY CYCLE (%)
Figure 22. SNR/SFDR vs. Clock Duty Cycle
0 –10 –20 –30 –40 –50 –60 –70 –80
AMPLITUDE (dBFS)
–90
–100 –110 –120
0 7.68 15.36 23.04 30.72
FREQUENCY (MHz)
Figure 23. 32K FFT CDMA-2000 Carrier @ F
61.44 MSPS
–40°C
+25°C
+85°C
SFDR (DCS OFF)
SNR (DCS ON)
= 46.08 MHz, Sample Rate =
IN
03066-0-045
03066-0-046
03066-0-060
95
–40°C
90
85
SFDR (dBc)
80
75
70
0 25 50 75 100 125
+85°C
+25°C
INPUT FREQUENCY (MHz)
03066-0-047
Figure 24. SFDR vs. Input Frequency
0 –10 –20 –30 –40 –50 –60 –70 –80
AMPLITUDE (dBFS)
–90
–100 –110 –120
0 7.68 15.36 23.04 30.72
Figure 25. 32K FFT WCDMA Carrier @ F
FREQUENCY (MHz)
=76.8 MHz,
IN
03066-0-061
Sample Rate = 61.44 MSPS
Rev. B | Page 13 of 36
AD9236

THEORY OF OPERATION

The AD9236 architecture consists of a front-end sample-and­hold amplifier (SHA) followed by a pipelined switched capacitor ADC. The pipelined ADC is divided into three sections, consisting of a 4-bit first stage followed by eight 1.5-bit stages and a final 3-bit flash. Each stage provides sufficient overlap to correct for flash errors in the preceding stages. 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 (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.
The input stage contains a differential SHA that can be ac- or dc-coupled in differential or single-ended modes. The output­staging block aligns the data, carries out the error correction, and passes the data to the output buffers. The output buffers are powered from a separate supply, allowing adjustment of the output voltage swing. During power-down, the output buffers go into a high impedance state.

ANALOG INPUT AND REFERENCE OVERVIEW

The analog input to the AD9236 is a differential switched capacitor SHA that has been designed for optimum performance while processing a differential input signal. The SHA input can support a wide common-mode range (VCM) and maintain excellent performance, as shown in input common-mode voltage of midsupply minimizes signal­dependant errors and provides optimum performance.
100
95
90
85
80
75
70
SNR/SFDR (dBc)
65
60
55
50
0.5 1.0 1.5 2.0 2.5 3.0
Figure 26. SNR, SFDR vs. Common-Mode Level
SNR (2.5MHz)
SNR (39MHz)
COMMON-MODE LEVEL (V)
SFDR (2.5MHz)
SFDR (39MHz)
Figure 26. An
03066-0-016
Referring to Figure 27, the clock signal alternately switches the SHA between sample mode and hold mode. When the SHA is switched into sample mode, the signal source must be capable of charging the sample capacitors and settling within one-half of a clock cycle. A small resistor in series with each input can help reduce the peak transient current required from the output stage of the driving source. In addition, a small shunt capacitor can be placed across the inputs to provide dynamic charging currents. This passive network creates a low-pass filter at the ADC’s input; therefore, the precise values are dependant upon the application. In IF undersampling applications, any shunt capacitors should be reduced or removed. In combination with the driving source impedance, they would limit the input bandwidth.
H
VIN+
VIN–
T
C
PAR
T
C
PAR
Figure 27. Switched-Capacitor SHA Input
5pF
5pF
T
T
H
03066-0-012
For best dynamic performance, the source impedances driving VIN+ and VIN– should be matched such that common-mode settling errors are symmetrical. These errors are reduced by the common-mode rejection of the ADC.
An internal differential reference buffer creates positive and negative reference voltages, REFT and REFB, that define the span of the ADC core. The output common mode of the reference buffer is set to midsupply, and the REFT and REFB voltages and span are defined as follows:
REFT = ½(AVDD + VREF)
REFB = ½(AVDD + VREF)
Span = 2 × (REFTREFB) = 2 × VREF
It can be seen from the previous equations that the REFT and REFB voltages are symmetrical about the midsupply voltage and, by definition, the input span is twice the value of the VREF voltage.
The internal voltage reference can be pin strapped to fixed values of 0.5 V or 1.0 V, or adjusted within the same range as discussed in the
Internal Reference Connection section. Maximum SNR performance is achieved with the AD9236 set to the largest input span of 2 V p-p. The relative SNR degradation is 3 dB when changing from 2 V p-p mode to 1 V p-p mode.
Rev. B | Page 14 of 36
AD9236
The SHA can be driven from a source that keeps the signal peaks within the allowable range for the selected reference voltage. The minimum and maximum common-mode input levels are defined as:
VCM
VCM
VREF
=
MIN
MAX
2
()
=
+
VREFAVDD
2
The minimum common-mode input level allows the AD9236 to accommodate ground referenced inputs.
Although optimum performance is achieved with a differential input, a single-ended source can be applied to VIN+ or VIN–. In this configuration, one input accepts the signal, while the opposite input should be set to midscale by connecting it to an appropriate reference. For example, a 2 V p-p signal can be applied to VIN+ while a 1 V reference is applied to VIN–. The AD9236 then accepts an input signal varying between 2 V and 0 V. In the single-ended configuration, distortion performance can degrade significantly as compared to the differential case. However, the effect is less noticeable at lower input frequencies.

Differential Input Configurations

As previously detailed, optimum performance is achieved while driving the AD9236 in a differential input configuration. For baseband applications, the AD8138 differential driver provides excellent performance and a flexible interface to the ADC. The output common-mode voltage of the AD8138 is easily set to AVDD/2, and the driver can be configured in a Sallen-Key filter topology to provide band limiting of the input signal.
33Ω
2V p-p
Figure 29. Differential Transformer-Coupled Configuration
49.9Ω
0.1μF
20pF
33Ω
1kΩ
1kΩ
The signal characteristics must be considered when selecting a transformer. Most RF transformers saturate at frequencies below a few MHz, and excessive signal power can also cause core saturation, which leads to distortion.

Single-Ended Input Configuration

A single-ended input can provide adequate performance in cost-sensitive applications. In this configuration, there is a degradation in SFDR and distortion performance due to the large input common-mode swing (see
Figure 14). However, if the source impedances on each input are matched, there should be little effect on SNR performance.
Figure 30 details a typical
single-ended input configuration.
1k
2V p-p
49.9
0.33μF
Ω
+
10μF 0.1μF
Ω
1k
Ω
33
Ω
20pF
1k
Ω
33
Ω
1k
Ω
AVDD
VIN+
AD9236
VIN–
AGND
VIN+
AD9236
VIN–
03600-0-014
AVDD
AGND
1V p-p
0.1μF
Figure 28. Differential Input Configuration Using the AD8138
1kΩ
1kΩ
49.9Ω
499Ω
523Ω
499Ω
AD8138
499Ω
33Ω
20pF
33Ω
AVDD
VIN+
AD9236
VIN–
AGND
03066-0-013
At input frequencies in the second Nyquist zone and above, the performance of most amplifiers is not adequate to achieve the true performance of the AD9236. This is especially true in IF undersampling applications where frequencies in the 70 MHz to 100 MHz range are being sampled. For these applications, differential transformer coupling is the recommended input configuration. The value of the shunt capacitor is dependent on the input frequency and source impedance and should be reduced or removed. An example is shown in
Figure 29.
Rev. B | Page 15 of 36
03600-A-015
Figure 30. Single-Ended Input Configuration

CLOCK INPUT CONSIDERATIONS

Typical high speed ADCs use both clock edges to generate a variety of internal timing signals, and as a result can be sensitive to clock duty cycle. Commonly a 5% tolerance is required on the clock duty cycle to maintain dynamic performance characteristics. The AD9236 contains a clock 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 AD9236. As shown in Figure 22, noise and distortion performance is nearly flat for a 30% to 70% duty cycle with the DCS on.
The duty cycle stabilizer uses a delay-locked loop (DLL) to create the nonsampling edge. As a result, any changes to the sampling frequency require approximately 100 clock cycles to allow the DLL to acquire and lock to the new rate.
AD9236

Jitter Considerations

High speed, high resolution ADCs are sensitive to the quality of the clock input. The degradation in SNR at a given input frequency
) due only to aperture jitter (tJ) can be calculated with the
(f
INPUT
following equation:
SNR
=
10
2
INPUT
log20
1
tf
×π
J
which is determined by the sample rate and the characteristics of the analog input signal.
425
400
375
ANALOG CURRENT
TOTAL POWER
140
120
100
80
In the equation, the rms aperture jitter represents the root­mean square of all jitter sources, which include the clock input, analog input signal, and ADC aperture jitter specification. IF undersampling applications are particularly sensitive to jitter
Figure 31).
(see
The clock input should be treated as an analog signal in cases where aperture jitter can affect the dynamic range of the AD9236. Power supplies for clock drivers should be separated from the ADC output driver supplies to avoid modulating the clock signal with digital noise. Low jitter, crystal controlled oscillators make the best clock sources. If the clock is generated from another type of source (by gating, dividing, or other methods), it should be retimed by the original clock at the last step.
75
70
65
60
55
SNR (dBc)
50
45
40
1 10 100 1000
Figure 31. SNR vs. Input Frequency and Jitter
INPUT FREQUENCY (MHz)
0.2ps
MEASURED SNR
0.5ps
1.0ps
1.5ps
2.0ps
2.5ps
3.0ps
03066-0-043

POWER DISSIPATION AND STANDBY MODE

As shown in Figure 32, the power dissipated by the AD9236 is proportional to its sample rate. The digital power dissipation is determined primarily by the strength of the digital drivers and the load on each output bit. The maximum DRVDD current
) can be calculated as
(I
DRVDD
= V
I
DRVDD
where
N is the number of output bits, 12 in the case of the
AD9236. This maximum current occurs when every output bit switches on every clock cycle, that is, a full-scale square wave at the Nyquist frequency, established by the average number of output bits switching,
DRVDD
DRVDDDRVDD
× C
× f
LOAD
f
CLK
× N
CLK
NfCVI
×××=
CLKLOAD
/2. In practice, the DRVDD current is
03066-0-044
60
CURRENT (mA)
40
20
0
350
POWER (mW)
325
DIGITAL CURRENT
300
10 20 30 40 50 60 70 80 90 100
Figure 32. Power and Current vs. Sample Rate @ 2.5 MHz
SAMPLE RATE (MSPS)
Reducing the capacitive load presented to the output drivers can minimize digital power consumption. The data in
Figure 32 was taken with the same operating conditions as the Typical Performance Characteristics, and with a 5 pF load on each output driver.
By asserting the PDWN pin high, the AD9236 is placed in standby mode. In this state, the ADC typically dissipates 1 mW if the CLK and analog inputs are static. During standby, the output drivers are placed in a high impedance state. Reasserting the PDWN pin low returns the AD9236 to its normal operational mode.
Low power dissipation in standby mode is achieved by shutting down the reference, reference buffer, and biasing networks. The decoupling capacitors on REFT and REFB are discharged when entering standby mode and then must be recharged when returning to normal operation. As a result, the wake-up time is related to the time spent in standby mode, and shorter standby cycles result in proportionally shorter wake-up times. With the recommended 0.1 μF and 10 μF decoupling capacitors on REFT and REFB, it takes approximately 1 second to fully discharge the reference buffer decoupling capacitors and 7 ms to restore full operation.

DIGITAL OUTPUTS

The AD9236 output drivers can be configured to interface with
2.5 V or 3.3 V logic families by matching DRVDD to the digital supply of the interfaced logic. The output drivers are sized to provide sufficient output current to drive a wide variety of logic families. However, large drive currents tend to cause current glitches on the supplies, which can affect converter performance. Applications requiring the ADC to drive large capacitive loads or large fanouts can require external buffers or latches.
As detailed in either offset binary or twos complement.
Table 1 1, the data format can be selected for
Rev. B | Page 16 of 36
AD9236

TIMING

The AD9236 provides latched data outputs with a pipeline delay of seven clock cycles. Data outputs are available one propagation delay (t
) after the rising edge of the clock signal. Refer to
PD
Figure 2 for a detailed timing diagram.
The length of the output data lines and the loads placed on them should be minimized to reduce transients within the AD9236. These transients can degrade the converter’s dynamic performance.
The lowest typical conversion rate of the AD9236 is 1 MSPS. At clock rates below 1 MSPS, dynamic performance can degrade.

VOLTAGE REFERENCE

A stable and accurate 0.5 V voltage reference is built into the AD9236. The input range can be adjusted by varying the reference voltage applied to the AD9236 using either the internal reference or an externally applied reference voltage. The input span of the ADC tracks reference voltage changes linearly. The various reference modes are summarized in and described in the following sections.
If the ADC is being driven differentially through a transformer, the reference voltage can be used to bias the center tap (common-mode voltage).

Internal Reference Connection

A comparator within the AD9236 detects the potential at the SENSE pin and configures the reference into four possible states, which are summarized in
Tabl e 10 . If SENSE is grounded, the reference amplifier switch is connected to the internal resistor divider (see
Figure 33), setting VREF to 1 V. Connecting the SENSE pin to VREF switches the reference amplifier output to the SENSE pin, completing the loop and providing a 0.5 V reference output. If a resistor divider is connected as shown in
Figure 34, the switch is again set to the SENSE pin. This puts the reference amplifier in a noninverting mode with the VREF output defined as follows:
Tabl e 10
In all reference configurations, REFT and REFB drive the A/D conversion core and establish its input span. The input range of the ADC always equals twice the voltage at the reference pin for either an internal or an external reference.
VIN+
10μF+0.1μF
10μF+0.1μF
VIN–
ADC
CORE
VREF
SELECT
LOGIC
SENSE
0.5V
AD9236
Figure 33. Internal Reference Configuration
VIN+ VIN–
VREF
R2 SENSE
R1
SELECT
LOGIC
AD9236
03066-A-017
ADC
CORE
0.5V
REFT
0.1μF
0.1μF 10μF
REFB
0.1μF
REFT
0.1μF
REFB
0.1μF
+
0.1μF 10μF
+
VREF
+×=
15.0
R1
Figure 34. Programmable Reference Configuration
03066-0-018
R2
Table 10. Reference Configuration Summary
Selected Mode SENSE Voltage Resulting VREF (V) Resulting Differential Span (V p-p)
External Reference AVDD N/A 2 × External Reference Internal Fixed Reference VREF 0.5 1.0 Programmable Reference 0.2 V to VREF
R2
15.0
⎜ ⎝
+×
R1
(See Figure 34)
2 × VREF
Internal Fixed Reference AGND to 0.2 V 1.0 2.0
Rev. B | Page 17 of 36
AD9236
If the internal reference of the AD9236 is used to drive multiple converters to improve gain matching, the loading of the reference by the other converters must be considered.
Figure 35 depicts how the internal reference voltage is affected by loading. A 2 mA load is the maximum recommended load.
0.05
0
–0.05
–0.10
ERROR (%)
–0.15
–0.20
1.0V ERROR (%)
0.5V ERROR (%)

OPERATIONAL MODE SELECTION

As discussed in the Digital Outputs section, the AD9236 can output data in either offset binary or twos complement format. There is also a provision for enabling or disabling the clock duty cycle stabilizer (DCS). The MODE pin is a multilevel input that controls the data format and DCS state. The input threshold values and corresponding mode selections are outlined in
Table 11. Mode Selection
MODE Voltage
Data Format
Duty Cycle Stabilizer
AVDD Twos Complement Disabled 2/3 AVDD Twos Complement Enabled 1/3 AVDD Offset Binary Enabled AGND (Default) Offset Binary Disabled
Tabl e 11 .
–0.25
0 0.5 1.0 1.5 2.0 2.5 3.0
Figure 35. VREF Accuracy vs. Load
LOAD (mA)
03066-0-019

External Reference Operation

The use of an external reference can be necessary to enhance the gain accuracy of the ADC or to improve thermal drift characteristics. When multiple ADCs track one another, a single reference (internal or external) can be necessary to reduce gain matching errors to an acceptable level.
Figure 36 shows the typical drift characteristics of the internal reference in both 1.0 V and 0.5 V modes.
When the SENSE pin is tied to AVDD, the internal reference is disabled, allowing the use of an external reference. An internal reference buffer loads the external reference with an equivalent 7 kΩ load. The internal buffer still generates the positive and negative full-scale references, REFT and REFB, for the ADC core. The input span is always twice the value of the reference voltage; therefore, the external reference must be limited to a maximum of 1.0 V.
1.0
0.9
0.8
0.7
0.6 = 1.0V
0.5
ERROR (%)
0.4
REF
V
0.3
0.2
0.1
0 –40–30–20–100 1020304050607080
Figure 36. Typical VREF Drift
V
REF
V
= 0.5V
REF
TEMPERATURE (°C)
03066-0-011

EVALUATION BOARD

The AD9236 evaluation board provides all of the support circuitry required to operate the ADC in its various modes and configurations. Complete schematics and layout plots follow and demonstrate the proper routing and grounding techniques that should be applied at the system level.
It is critical that signal sources with very low phase noise (< 1 ps rms jitter) be used to realize the ultimate performance of the converter. Proper filtering of the input signal, to remove harmonics and lower the integrated noise at the input, is also necessary to achieve the specified noise performance.

TSSOP Evaluation Board

Figure 37 shows the typical bench setup used to evaluate the ac performance of the AD9236. The AD9236 can be driven single­ended or differentially through an AD8138 driver or a transformer. Separate power pins are provided to isolate the DUT from the support circuitry. Each input configuration can be selected by proper connection of various jumpers (refer to the schematics).
The AUXCLK input should be selected in applications requiring the lowest jitter and SNR performance (that is, IF undersampling characterization). It allows the user to apply a clock input signal that is 4× the target sample rate of the AD9236. A low jitter, differential divide-by-4 counter, the MC100LVEL33D, provides a 1× clock output that is subsequently returned back to the CLK input via JP9. For example, a 260 MHz signal (sinusoid) is divided down to a 65 MHz signal for clocking the ADC. Note that R1 must be removed with the AUXCLK interface. Lower jitter is often achieved with this interface since many RF signal generators display improved phase noise at higher output frequencies and the slew rate of the sinusoidal output signal is 4× that of a 1× signal of equal amplitude.
Rev. B | Page 18 of 36
AD9236

LFCSP Evaluation Board

The typical bench setup used to evaluate the ac performance of the AD9236 is similar to the TSSOP evaluation board connections. The AD9236 can be driven single-ended or differentially through a transformer. Separate power pins are provided to isolate the DUT from the support circuitry. Each input configuration can be selected by proper connection of various jumpers (see
Figure 48).
An alternative differential analog input path using an AD8351 op amp is included in the layout but is not populated in production. Designers interested in evaluating the op amp with the ADC should remove C15, R12, and R3 and populate the op amp circuit. The passive network between the AD8351 outputs and the AD9236 allows the user to optimize the frequency response of the op amp for their application.
3V
–+
DVDD
J1
DATA
CAPTURE
AND
PROCESSING
03066-0-024
REFIN
SIGNAL SYNTHESIZER
10MHz REFOUT
CLOCK SYNTHESIZER
HP8644, 2V p-p
HP8644, 2V p-p
BAND-PASS
FILTER
CLOCK
DIVIDER
3V
–+
AVDD DUT
S4 XFMR INPUT
S1 CLOCK
3V
–+
GND GND DUT
AVDD
3V
–+
DRVDD
AD9236
EVALUATION BOARD
Figure 37. TSSOP Evaluation Board Connections
Rev. B | Page 19 of 36
AD9236
03066-0-007
μF
DUTDRVDD
1
0
0
DUTCLK
WHT
D11O
D10O
D9O
D8O
D7O
D6O
D5O
D4O
D3O
D2O
D1O
D0O
OTRO
TP6
4
.0
C
0
TP5
WHT
272625
28
D11
D10
OTRAVDD
AD9236
C39
0.001μF
0.1μF
C57
C36
10V
C22
10μF
JP24
JP25
C35
0.1μF
10V
C21
0.1μF
10μF
DUTAVDD
JP22
JP23
WHT
TP17
SENSE
AGND
71
8
3
21
22
D7
D8
D9
PDWN
REFB
VREF
4
5
14
C33
C34
10V
0.1μF
18
191716
D4
D5MODE
D3
D6
U1
VIN+
VIN–
REFT
220
6
9
10
VIN+
VIN–
C50
0.1μF
C32
C20
10μF
13
15
D0
D1
D2
CLK
AVDD
DGND
DRVDD
AGND
11
24
23
12
0.1μF
0.1μF
JP7
JP6
DUTAVDD
C37
0.1μF
C1
10V
10μF
C41
0.001μF
C38
0.1μF
10V
C23
10μF
JP2
JP1
8
22Ω
RP5
1
D8O D8
D0
817 22Ω
RP3
D0O
D9
765
22Ω
22Ω RP5
RP5
2
3
D9O
D1
6
22Ω
22Ω
RP3
RP3
2
3
D1O
D10
22Ω RP5
D10O
D2
22Ω RP3 54
D2O
4
D11
D11O
D3
D3O
10kΩ
R3
10kΩ
OTR
8
7
6
22Ω
22Ω
22Ω
22Ω
RP62
D5
D5O
RP6 5
RP63
4
D7
D6
22Ω
22Ω
RP4 63
RP4 54
D7O
D6O
RP61
D4
8
22Ω
22Ω RP4 72
RP4 1
D4O
JP12
RED
TP2
L1
OTRO
FBEAD
R4
DUTAVDD
AVDD
RED
TP1
12
F
C59
0.1μF
21
C58
22μF
2
TB1
DUTAVDDIN
25V
L2
FBEAD
TB1 3
AGND
TB1 1
AVDDIN
R20
1kΩ
AVDD
R27
5kΩ
JP13
AVDD
C52
0.1μF
C47
25V
22μF
RED
TP3
L3
FBEAD
R17
1kΩ
DUTDRVDD
JP11
12
C48
5
TB1
DRVDDIN
R42
1kΩ
BLK
TP16
BLK
BLK
TP14
BLKBLK
TP13
TP10 TP15
BLK BLK
TP12
TP9
DVDD
RED
TP4
L4
C53
0.1μF 21
FBEAD
25V
22μF
6
TB1 4
AGND
DVDDIN
TB1
BLK
TP11
C14
0.1μF
C6
25V
22μF
Figure 38. TSSOP Evaluation Board Schematic, DUT
Rev. B | Page 20 of 36
AD9236
864
2
16
14
12
10
24
22
20
18
32
30
28
26
40
38
36
34
HEADER RIGHT ANGLE MALE NO EJECTORS
957
3
1
DD0
16
22Ω
1
22Ω
DD1
15
22Ω
11
DD2
22Ω
13
DD3
DD4
121314
22Ω
15
17
DD5
22Ω
DD6
22Ω
RP17RP18RP16RP15RP14RP13RP12RP1
23
21
19
DD7
DD8
16
10911
22Ω
22Ω
RP2
1
31
29
27
25
DD9
DD10
DD11
DOTR
1514131211
22Ω
22Ω
22Ω
22Ω
RP22RP23RP24RP25RP26RP2
39
37
35
33
DACLK
9
10
22Ω
22Ω
22Ω
RP2
8
7
03066-0-008
J1
DVDD
182
15
16
10
U7
74VHC541
G2 GND
19
17
Y2Y3Y4Y5Y6Y7Y8
A2A3A4A5A6A7A8
A1 Y1
3
D9
D8
D11
D10
AVDD
R18
500Ω
R2
10kΩ
CW
20
10μF
VCC
21
10V
C12
C4
0.1μF
10μF
21
10V
20
10
VCC
182
14
15
16
17
Y2Y3Y4Y5Y6Y7Y8
C5
11
12
13
C11
0.1μF G1
U6
74VHC541
G2 GND
A1 Y1
19
D0
R26
10kΩ
NC
MC100LVEL33D
VCC
8
A2A3A4A5A6A7A8
654
3
D6
D5
D4
D3
D2
D1
4
321
INA
INB
INCOM
U3
OUT
AVDD
VEE
REF
AVDD
657
C28
987
D7
10V
10μF
0.1μF
C24
U3 DECOUPLING
113Ω
R13
G1
1
AVDD
1N5712
D1
R25
10kΩ
D2
1N5712
2
1
T1-1T
6
T2
5
43
1
0.1μF
C26
90Ω
R15
11
12
13
14
987
654
OTR
R9
22Ω
DUTCLK
JP4
JP3
R7
22Ω
43
65
74VHC04
U8
AGND;7
AVDD ;1 4
74VHC04
U8
10V
10μF
C3
0.1μF
C10
U8 DECOUPLING
AVDD
1213
74VHC04
U8
89
1011
74VHC04
U8
74VHC04
U8
21
74VHC04
U8
WHT
TP7
R19
500Ω
C13
AVDD
C27
0.1μF
R11
AUXCLK
S5
49.9Ω
1
2
113Ω
R12
R14
90Ω
AVDD
JP9
CLOCK
0.1μF
R1
49.9Ω
1
2
S1
Figure 39. TSSOP Evaluation Board Schematic, Clock Inputs and Output Buffering
Rev. B | Page 21 of 36
AD9236
AVDD
VIN+
DNP
C44
R21
33Ω
JP42
JP40
JP45
C7
0.1μF
1kΩ
R23
R41
1kΩ
C44B
20pF
VIN–
DNP
C43
R22
33Ω
JP46
JP41
JP43
1kΩ
AVDD
R16
1
2
3
T1-1T
T1
6
5
4
03066-A-009
C16
0.1μF
C25
0.33μF
R8
1kΩ
JP5
40Ω
AD8138
5
VEE
2
S2
VAL C45
49.9Ω
R24
1
2
S4
XFMR INPUT
C17VAL
R36
499Ω
6
C18
R31
49.9Ω
10V
0.1μF
RED
TP8
ALT VEE
31
JP8
2
AB
C19
10μF
12
C9
0.33μF
49.9Ω
R5
C8
1
2
S3
SINGLE INPUT
R32
1kΩ
AVDD
21
10V10μF
+
C15
AVDD
0.1μF
1kΩ
R33
VAL
C69
0.33μF
C2
VAL C42
R6
R37
499Ω
3
R10
40Ω
2
VOC
4
VO+
VO–
U2
VCC
+IN
–IN
8
1
R34
R35
523Ω
499Ω
1
AMP INPUT
Figure 40. TSSOP Evaluation Board Schematic, Analog Inputs
Rev. B | Page 22 of 36
AD9236
DACLK
DD0 DD1
DD2 DD3 DD4 DD5 DD6 DD7 DD8
DD9 DD10 DD11
1 2
DB10
3
DB19
4
DB8
AD9762
5
DB7
6
DB6
7
DB5 DB4 DB3 DB2 DB1 DB0 NC1 NC2
U4
8
9 10 11 12
13 14
CLOCKMSB–DB11
DVDD
DCOM
NC3
AVDD
COMP2
IOUTA IOUTB ACOM
COMP1
FSADJ
REFIO
REFLO
SLEEP
28 27
26 25 24 23 22 21 20 19 18 17 16 15
C30
0.1μF
C49
0.01μF
C56
0.01μF
R30 2kΩ
C31
0.01μF
DVDD
C29
0.1μF
C51
0.01μF
C46
0.01μF TP18
WHT
R29
49.9Ω
C55
22pF
R28
49.9Ω
C54
22pF
03066-0-010
S6
Figure 41. TSSOP Evaluation Board Schematic, Optional D/A Converter
Figure 42. TSSOP Evaluation Board Layout, Primary Side
Rev. B | Page 23 of 36
03066-0-025
AD9236
Figure 43. TSSOP Evaluation Board Layout, Secondary Side
03066-0-026
Figure 44. TSSOP Evaluation Board Layout, Ground Plane
Rev. B | Page 24 of 36
03066-0-027
AD9236
Figure 45. TSSOP Evaluation Board Layout, Power Plane
03066-0-028
Figure 46. TSSOP Evaluation Board Layout, Primary Silkscreen
Rev. B | Page 25 of 36
03066-0-029
AD9236
03066-0-030
Figure 47. TSSOP Evaluation Board Layout, Secondary Silkscreen
Rev. B | Page 26 of 36
AD9236
X
6
1 H
D N G
E L O H T
M
1
P6
AVDD
EXTREF
1V MAX E1
6 E L O H T
2 H
M
6
6
E
E
L
L
O
O
H
H
T
T
4
3
H
M
H
M
P2
6
45
123
MODE
2
2
Ω
5
k
R
1
F
2
μ
2
0
C
1
C13
0.10μF P11
D
D D
C
V A
P8
B
P9
A
GND
P7
R1
10kΩ
5.0V
VAMP
VDL
2.5V
GND
2.5V
DRVDD
GND
3.0V
AVDD
C8
0.1μF
P5
7 R
GND
GND
Ω
k 1
p10
3
P3
Ω
6
k
R
1
C9
0.1μF
C12
R9
10kΩ
P1
E
IT B
E G N A R R E V O
GND
0.10μF
GND GND
X R D
6 1
Ω
0 2
2 2 P R
1
) B S
(M
4
P4
GND
0.1μF
C11
C29
10μF
D N G
X
X
X
1
2
3
1
1
1
D
D
D
5
3
4
1
1
1
2
3
4
17 18 19 20 21 22 23 24
C7
0.1μF
. 8 1
C D N
T
, A
U
6
P
, C
IN
2 4
D E
, R
D
9
N
1
E
, R
E
8
L
1
G
R
IN
E
S
C
R
A L
O
P
F
X
0
X
X
7
1
9
8
D
D
D
D
0
1
2
9
1
1
1
5
6
7
8
D8 D9
D10 D11
OTR
MODE
SENSE
VREF
25262728303132
E B
D L
GND
U O H
7 1
S E
, C
N
2 4
O Y
, R
L
2
.
N
1
7
O
R
2 C
D
2
N
4 R
, A 7 1
, C 5 1
, C 2 1
, R 3
R
6
E
C
V O M E R
D D V R D
6 1
D D V R D
REFB
D N G
D D V A
. E
IM T A
T A
D R A O
B N O
Ω
0
F
μ
.1 0
D N G
5 1
D N G D
T F E R
6 2 R
6 3 R
4 1
7
6
D
D
AD9236
D
D
N
D V
G
A
A
D
D
D
N
V
G
A
Ω
k 1
Ω
k 1
2 1 R
IN P M A
U4
X
X 6 D
6 1
1
2
3
1
1
5 D
+ IN
V
29
+ IN
V
X
X
X
X
4
5
D
D
5
4
1
1
2
3
0 1
11
4
3
D
D
D
N G
IN
A
V
D N
IN V
G
1 2 C
Ω
4
3
R
3
OUT
X
3
2
D
D
2
3
1
1
4
5
9
2 D
D D V A
D D V A
F p 0 1
6 2 C
0
Ω
1
6
R
3
6
T 1
ADT1–1WT
H n 0
1 1 L
1 J
1 D
0
1
1
1
6
7
) B S
(L
D N G
F p 0
1
5 4 E
CT
2
5
1
XFRIN1
5 1 C
X 0 D
9
8
D1
8
D0
7
DNC
6
DNC
5
PDWN
4
DNC
3
CLK
2
DNC
1
1 L R O
9
F
1
p 0
C
2
2
X
R
X
D
D
N
N
G
G
5 C
F
μ
6 1
.1
C
0
C E S
I R
34
P
NC
D N G
F
μ
.1 0
P M A
D N G
Ω
0 2
2 1 P R
R
D
E
N G
ILT F R O
F
F
μ
.1 0
1
Ω
1
6
R
3 D
N G
OPTIONAL XFR
R E
:
ID
R
IV
E P
D
M
E
U
G A
J
T
E
L
L
O
B A
V
R
L
E
A
D
N
L
R
O
E T
S
X
IN
E
P
:
E
A
S
O
N E
T
S
E
3 2 C
B
OUT
X
T2
) T L U A F E
E
(D
C
E
N
C
E
E
N
C
R
E
N
E
R
E
F
E
E
R
F
E
E
R
F
V
R
E
V
.5
R
1
0
L
L
L
A
A
A
N
N
N
R
R
R
E
E
E
T
T
T
X
IN
E
IN
:
:
:
B
C
D
O
O
O
T
T
T
E
E
E
Ω
8
k
R
1
K L C
F p 0 1
3
Ω
R
0
T
OUT
C
X
4
2
5
1
3
FT C1–1–13
IN R F X
F F
:
O S
R E
C
P
D
/
M
T
U
N E
J E
M
L
E
B
L
A
P
R
M
E
O
D
C
L
S
O
O
S
W
IN
T :
P E
1
D
O
O
T
M
5
P14
5
Ω
1
3
R
3
B IN
P M A
B
OUT
X
D N G
N O
F
S
F
N
C
O
O
/D
S
T
S
C
N
C
E
/D
/D
M
Y
Y
E
R
R
L
A
A
P
IN
IN
M O
B
B
T
T
C
E
E
S
S
S
O
F
F
F
F
W
O
O
T
:
:
:
4
3
2
O
O
O
T
T
T
5
5
5
D N G
P13
D D V A
D N G
D D V A
F
μ
8 1 C
0.10
R SINGLE ENDED
R18
C E S I R P
03066-A-050
5
Ω
2
k
R
1
3
Ω
1
k
R
1
D N G
Ω
5 2
R3, R16, C18
ONLY ONE SHOULD BE
ON BOARD AT A TIME
Figure 48. LFCSP Evaluation Board Schematic, Analog Inputs and DUT
Rev. B | Page 27 of 36
AD9236
GND
03066-A-051
135791113151719212325272931333537
135791113151719212325272931333537
P12
HEADER 40
2468101214161820222426283032343638
2468101214161820222426283032343638
GNDDRGND
MSB
39
39
40
40
AMPIN
AMPINB
DRY
GND
GND
GND
GND
C24
10μF
C45
0.1μF
R14
25Ω
R39
1kΩ
VAMP
VOCM
OPHI
R38
1kΩ
C44
0.1μF
VPOS
8
9
10
C27
R16
0.1μF
0Ω
OPLO 7
C17
R17
GND
COMM 6
0.1μF
0Ω
DRY
GND
GND
DRVDD
GND
24232221201918171615141312111098765432
CC
2Q4
2Q2
2Q3
GND
GND
GND
2Q6
2D6
D12X
2Q5
2D5
D11X
V
GND
CC
2D3
2D4
V
DRVDD
D10X
2D2
GND
D8X
D9X
GND
2Q7
2OE
2QB
U1
74LVTH162374
2CLK
2DB
2D7
2526272829303132333435363738394041424344454647
DRX
CLKAT/DAC
D13X
MSB
2Q1
2D1
D7X
1Q8
1D8
D6X
1Q7
1D7
D5X
GND
GND
GND
GND
1Q6
1D6
D4X
1Q5
1D5
D3X
Figure 49. LFCSP Evaluation Board Schematic, Digital Path
DRVDD
V
V
CC
DRVDD
TO USE AMPLIFIER
PLACE ALL COMPONENTS
SHOWN HERE (RIGHT)
GND
VAMP
EXCEPT R40 OR R41.
REMOVE R12, R3, R18, R42, C6,
R40
R41
U3
AD8351
C15, AND C18.
10kΩ
10kΩ
PWDN 1
INHI 3
RGP1 2
C28
0.1μF
AMP IN
AMP
VAMP
GND
GND
1
1Q4
1Q3
1Q2
GND
CC
1D4
1D3
GND
1D2
D2X
D1X
D0X
GND
LSB
1Q1
1OE 1
1D1
1CLK
48
CLKLAT/DAC
OUT
IN
GND
POWER DOWN
USE R40 OR R41
INLO 4
C35
R19
50Ω
R34
1.2kΩ
RPG2 5
R33
25Ω
0.10μF R35
25Ω
GND
GND
GND
Rev. B | Page 28 of 36
AD9236
C40
0.001μF
03066-A-052
C37
C46
0.1μF
10μF
DRVDD
C20
10μF
VDL
C48
C41
C47
C1
C39
C38
C36
C34
C31
C30
GND
C49
0.001μF
0.001μF
0.1μF
0.1μF
0.001μF
0.001μF
0.1μF
0.1μF
0.1μF
0.001μF
C2
10μF
GND
0.1μF
VAMP
LATCH BYPASSING
GND
SCHEMATIC SHOWS TWO GATE DELAY SETUP.
FOR ONE DELAY, REMOVE R22 AND R37 AND
ATTACH Rx (Rx = 0Ω).
R23
367
1Y
A
B
1
1
1
245
R32
2Y
A
2
GND
1kΩ
ENCX
74VCX86
Rx
R37
0Ω
8
GND
B
2
DNP
25Ω
CLKLAT/DAC
R22
0Ω
DR
VDL
14
11
PWR
4Y
3Y
A
3 9
B
3 10
GND
U5
A
B
4
4
12
13
R20
1kΩ
GND
R21
1kΩ
GND
R24
1kΩ
GND
E51
CLK
R28
ENC
E50
R27
0Ω
ENCX
0Ω
ENC
C14
0.001μF
C33
0.1μF
C32
0.001μF
C25
10μF
AVDD
C3
10μF
DRVDD AVDD
C4
C10
10μF
10μF
VDL
GND
GND
ANALOG BYP AS SING DIGITAL BYPASSING LATCH BYPASSING
CLOCK TIMING ADJUSTMENTS
FOR A DIRECT ENCODE USE R27
FOR A BUFFERED ENCODE USE R28
DUT BYP AS SING
E52 E53
VDL
VDL
R31
1kΩ
VDL
C43
0.1μF
ENCODE
J2
E31 E35
R30
R29
VDL
E43 E44
1kΩ
GND
50Ω
GND
GND
VDL
Figure 50. LFCSP Evaluation Board Schematic, Clock Input
Rev. B | Page 29 of 36
AD9236
03066-0-055
03066-0-053
Figure 51. LFCSP Evaluation Board Layout, Primary Side
03066-0-054
Figure 52. LFCSP Evaluation Board Layout, Secondary Side
Figure 53. LFCSP Evaluation Board Layout, Ground Plane
03066-0-056
Figure 54. LFCSP Evaluation Board Layout, Power Plane
Rev. B | Page 30 of 36
AD9236
Figure 55. LFCSP Evaluation Board Layout, Primary Silkscreen
03066-0-057
Figure 56. LFCSP Evaluation Board Layout, Secondary Silkscreen
03066-0-058
Rev. B | Page 31 of 36
AD9236
Table 12. LFCSP Evaluation Board Bill of Materials
Recommended
Item Qty. Omit1Reference Designator Device Package Value
18 C1, C5, C7, C8, C9, C11, C12,
1
Chip Capacitors 0603 0.1 μF
Vendor/Part No.
C13, C15, C16, C31, C33, C34, C36, C37, C41, C43, C47
8 C6, C18, C27, C17, C28,
C35, C45, C44
8 C2, C3, C4, C10, C20,
2
Tantalum Capacitors TAJC 10 μF
C22, C25, C29
2 C46, C24
3 8 C14, C30, C32, C38,
Chip Capacitors 0603 0.001 μF
C39, C40, C48, C49
4 1 C19 Chip Capacitor 0603 20 pF
1 C26
5
Chip Capacitors 0603 10 pF
2 C21, C23
9 E31, E35, E43, E44,
6
Headers EHOLE Jumper Blocks
E50, E51, E52, E53
2 E1, E45
7 2 J1, J2 SMA Connectors/50 Ω SMA
8 1 L1 Inductor 0603 10 nH Coilcraft/0603CS-
10NXGBU
9 1 P2 Terminal Block TB6 Wieland/25.602.2653.0,
z5-530-0625-0
10 1 P12 Header Dual 20-Pin RT Angle HEADER40 Digi-Key S2131-20-ND
5 R3, R12, R23, R28, RX 11
Chip Resistors 0603 0 Ω
6 R37, R22, R42, R16, R17, R27
12 2 R4, R15 Chip Resistors 0603 33 Ω
13 14 R5, R6, R7, R8, R13, R20,
Chip Resistors 0603 1 kΩ R21, R24, R25, R26, R30, R31, R32, R36
14 2 R10, R11 Chip Resistors 0603 36 Ω
1 R29 15
Chip Resistor 0603 50 Ω
1 R19
16 2 RP1, RP2 Resistor Pack R_742 220 Ω Digi-Key
CTS/742C163221JTR
17 1 T1 ADT1-1WT AWT1-1T Mini-Circuits
18 1 U1 74LVTH162374 CMOS Register TSSOP-48
19 1 U4 AD9236BCP ADC (DUT) CSP-32 Analog Devices, Inc. X
20 1 U5 74VCX86M SOIC-14 Fairchild
21 1 PCB AD92XXBCP/PCB PCB Analog Devices, Inc. X
22 1 U3 AD8351 Op Amp MSOP-8 Analog Devices, Inc. X
23 1 T2 M/A-COM Transformer ETC1-1-13 1-1 TX M/A-COM/ETC1-1-13
24 5 R9, R1, R2, R38, R39 Chip Resistors 0603 SELECT
25 4 R18, R14, R33, R35 Chip Resistors 0603 25 Ω
26 2 R40, R41 Chip Resistors 0603 10 kΩ
27 1 R34 Chip Resistor 1.2 kΩ
81 35
To ta l
1
These items are included in the PCB design, but are omitted at assembly.
Supplied by ADI
Rev. B | Page 32 of 36
AD9236
C
Y

OUTLINE DIMENSIONS

9.80
9.70
9.60
PIN 1
0.15
0.05
OPLANARIT
0.10
28
0.65 BSC
0.30
0.19
COMPLIANT TO JEDEC STANDARDS MO-153-AE
1.20 MAX
SEATING
PLANE
15
4.50
4.40
4.30
0.20
0.09
6.40 BSC
8° 0°
0.75
0.60
0.45
141
Figure 57. 28-Lead Thin Shrink Small Outline Package [TSSOP]
(RU-28)
Dimensions shown in millimeters
0.08
0.60 MAX
25
24
EXPOSED
PAD
(BOTTOM VIEW)
17
16
32
8
9
1
3.50 REF
PIN 1 INDICATOR
3.25
3.10 SQ
2.95
0.25 MIN
PIN 1
INDICATOR
1.00
0.85
0.80
12° MAX
SEATING PLANE
5.00
BSC SQ
TOP
VIEW
0.80 MAX
0.65 TYP
0.30
0.23
0.18
COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2
4.75
BSC SQ
0.20 REF
0.05 MAX
0.02 NOM
0.60 MAX
0.50
BSC
0.50
0.40
0.30
COPLANARITY
Figure 58. 32-Lead Frame Chip Scale Package [LFCSP_VQ]
5 mm × 5 mm Body, Very Thin Quad
(CP-32-2)
Dimensions shown in millimeters
Rev. B | Page 33 of 36
AD9236

ORDERING GUIDE

Model Temperature Range Package Description Package Option
AD9236BRU-80 –40°C to +85°C 28-Lead Thin Shrink Small Outline Package (TSSOP) RU-28 AD9236BRURL7-80 –40°C to +85°C 28-Lead Thin Shrink Small Outline Package (TSSOP) RU-28 AD9236BRUZ-80 AD9236BRUZRL7-80 AD9236BCP-80 AD9236BCPRL7-80 AD9236BCPZ-80 AD9236BCPZRL7-80 AD9236BRU-80EB TSSOP Evaluation Board AD9236BCP-80EB
1
Z = Pb-free part.
2
It is recommended that the exposed paddle be soldered to the ground plane for the LFCSP. There is an increased reliability of the solder joints, and the maximum
thermal capability of the package is achieved with the exposed paddle soldered to the customer board.
1
1
2
2
1, 2
1, 2
2
–40°C to +85°C 28-Lead Thin Shrink Small Outline Package (TSSOP) RU-28 –40°C to +85°C 28-Lead Thin Shrink Small Outline Package (TSSOP) RU-28 –40°C to +85°C 32-Lead Lead Frame Chip Scale (LFCSP_VQ) CP-32-2 –40°C to +85°C 32-Lead Lead Frame Chip Scale (LFCSP_VQ) CP-32-2 –40°C to +85°C 32-Lead Lead Frame Chip Scale (LFCSP_VQ) CP-32-2 –40°C to +85°C 32-Lead Lead Frame Chip Scale (LFCSP_VQ) CP-32-2
LFCSP Evaluation Board
Rev. B | Page 34 of 36
AD9236
NOTES
Rev. B | Page 35 of 36
AD9236
NOTES
© 2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. C03066-0-1/06(B)
Rev. B | Page 36 of 36
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