AD9238 Analog Devices, AD9238 Datasheet
AD9238
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AD9238 Summary of contents
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... Battery-powered instruments Hand-held scopemeters Low cost, digital oscilloscopes GENERAL DESCRIPTION The AD9238 is a dual 12-bit, 20 MSPS/40 MSPS/65 MSPS analog-to-digital converter (ADC). It features dual high performance sample-and-hold amplifiers (SHAs) and an integrated voltage reference. The AD9238 uses a multistage differential pipelined architecture with output error correction ...
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... Changes to Terminology Section ................................................. 10 Changes to Figure 29 ...................................................................... 15 Changes to Clock Input and Considerations Section ................ 17 Changes to Figure 33 ...................................................................... 18 Changes to Data Format Section .................................................. 19 Added AD9238 LQFP Evaluation Board Section ...................... 21 Added Dual ADC LFCSP PCB Section ....................................... 34 Added Thermal Considerations Section ..................................... 44 Updated Outline Dimensions ....................................................... 45 Changes to Ordering Guide .......................................................... 46 Rev Page ...
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... Changes to AC Specifications ......................................................... 4 Changes to Figure 1 .......................................................................... 4 Changes to Ordering Guide ............................................................ 5 Changes to TPCs 2, 3, and 6 ........................................................... 8 Changes to Clock Input and Considerations Section ................ 13 Added Text to Data Format Section ............................................ 15 Changes to Figure 9 ........................................................................ 16 Added Evaluation Board Diagrams Section ............................... 17 Update Outline Dimensions ......................................................... 24 2/03—Revision 0: Initial Version Rev Page AD9238 ...
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... IV 2.7 3.0 3.6 2.7 IV 2.25 3.0 3.6 2. ±0.01 V 180 VI 190 212 V 2.0 V ±0.1 V ±0.05 Rev Page AD9238BST/BCP-65 Typ Max Min Typ Max 12 12 ±0.50 ±1.1 ±0.50 ±1.1 ±0.50 ±2.4 ±0.50 ±2.5 ±0.35 ±0.35 ±0.35 ±0.8 ±0.35 ±1.0 ±0.60 ±0.70 ±0.50 ±1.4 ±0.55 ±1.75 ±4 ± ...
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... AD9238BST/BCP-40 AD9238BST/BCP-65 Min Typ Max Min Typ 70.4 70.3 70.1 69.7 70.3 69.3 68.7 70.0 68.3 67.6 70.2 70.1 69.9 69.4 70.1 68.9 68.1 69.1 67.9 66.6 11.5 11.4 11.4 11.3 11.4 11.2 11.1 11.3 11.1 10.9 −85.0 −80.0 86.0 86.0 85.0 76.7 86.0 80.0 72.5 80.5 75.0 −85.0 −85.0 AD9238 Max Unit Bits Bits Bits Bits Bits Bits Bits Bits dBc dBc dBc dBc dBc dBc dBc dBc dBc dBc dBc dB ...
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... Full OUT-OF-RANGE RECOVERY TIME Full 1 The AD9238-65 model has a duty cycle stabilizer circuit that, when enabled, corrects for a wide range of duty cycles (see Figure 24). 2 Output delay is measured from clock 50% transition to data 50% transition, with load on each output. 3 Wake-up time is dependent on the value of the decoupling capacitors; typical values shown with 0.1 μF and 10 μF capacitors on REFT and REFB. ...
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... V to DRVDD + 0.3 V ESD CAUTION −0 AVDD + 0.3 V −0 AVDD + 0.3 V −0 AVDD + 0.3 V −0 AVDD + 0.3 V −0 AVDD + 0.3 V −0 AVDD + 0.3 V −40°C to +85°C 150°C 300°C −65°C to +150°C = 54°C/W; 64-lead LFCSP, θ JA Rev Page AD9238 ...
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... DNC = DO NOT CONNECT Figure 3. 64-Lead LQFP Pin Configuration AGND 1 PIN 1 INDICATOR 2 3 AGND 4 AVDD AD9238 VREF 8 64-LEAD LFCSP 9 TOP VIEW 10 (Not to Scale) 11 AVDD 12 AGND AGND 16 NOTES 1. THERE IS AN EXPOSED PAD THAT MUST CONNECT TO AGND. ...
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... SHARED_REF Shared Reference Control Bit (Low for Independent Reference Mode, High for Shared Reference Mode). 63 CLK_A Clock Input Pin for Channel A. EP For the 64-Lead LFCSP only, there is an exposed pad that must connect to AGND. Rev Page AD9238 ...
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... AD9238 TERMINOLOGY Aperture Delay SHA performance measured from the rising edge of the clock input to when the input signal is held for conversion. Aperture Jitter The variation in aperture delay for successive samples, which is manifested as noise on the input to the ADC. Integral Nonlinearity (INL) 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 ...
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... MHz Figure 8. AD9238-65 Single-Tone SNR/SFDR vs. FS with MHz MHz Figure 9. AD9238-40 Single-Tone SNR/SFDR vs. FS with MHz 120 MHz Figure 10. AD9238-20 Single-Tone SNR/SFDR vs. FS with 126 MHz IN Rev Page 100 95 90 SFDR SNR 70 65 ...
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... Figure 11. AD9238-65 Single-Tone SNR/SFDR vs. AIN with f 100 90 80 SNR SFDR 70 SNR SNR –35 –30 –25 –20 –15 INPUT AMPLITUDE (dBFS) Figure 12. AD9238-40 Single-Tone SNR/SFDR vs. AIN with f 100 90 SNR SFDR 80 70 SNR SNR –35 –30 –25 –20 –15 INPUT AMPLITUDE (dBFS) Figure 13 ...
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... MHz Figure 21. Dual-Tone SNR/SFDR vs. AIN with f IN 100 – 201 MHz IN Rev Page AD9238 SNR SFDR SNR SNR –21 –18 –15 –12 –9 INPUT AMPLITUDE (dBFS MHz and SNR SFDR SNR SNR – ...
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... SAMPLE RATE (MSPS) Figure 26. Analog Power Consumption vs. FS 1.0 0.8 0.6 0.4 0 500 1000 1500 2000 2500 3000 CODE Figure 27. AD9238-65 Typical INL 1.0 0.8 0.6 0.4 0 500 1000 1500 2000 2500 3000 CODE Figure 28. AD9238-65 Typical DNL 60 3500 4000 3500 4000 ...
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... EQUIVALENT CIRCUITS AVDD VIN+_A, VIN–_A, VIN+_B, VIN–_B Figure 29. Equivalent Analog Input Circuit DRVDD Figure 30. Equivalent Digital Output Circuit AVDD CLK_A, CLK_B DCS, DFS, MUX_SELECT, SHARED_REF Figure 31. Equivalent Digital Input Circuit Rev Page AD9238 ...
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... ANALOG INPUT The analog input to the AD9238 is a differential, switched- capacitor, SHA that has been designed for optimum perfor- mance while processing a differential input signal. The SHA input accepts inputs over a wide common-mode range. An input common-mode voltage of midsupply is recommended to maintain optimal performance ...
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... Undersampling applications are particularly sensitive to jitter. For optimal performance, especially in cases where aperture jitter may affect the dynamic range of the AD9238 important to minimize input clock jitter. The clock input circuitry should use stable references; for example, use analog power and ground planes to generate the valid high and low digital levels for the AD9238 clock input ...
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... Each speed grade dissipates a baseline power at low sample rates that increases with clock frequency. Either channel of the AD9238 can be placed into standby mode independently by asserting the PDWN_A or PDWN_B pins recommended that the input clock(s) and analog input(s) remain static during either independent or total standby, which results in a typical power consumption for the ADC ...
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... VOLTAGE REFERENCE A stable and accurate 0.5 V voltage reference is built into the AD9238. The input range can be adjusted by varying the reference voltage applied to the AD9238, using either the internal reference with different external resistor configurations or an externally applied reference voltage. The input span of the ADC tracks reference voltage changes linearly ...
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... 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 the internal reference of the AD9238 is used to drive multiple converters to improve gain matching, the loading of the reference by the other converters must be considered. Figure 38 depicts how the internal reference voltage is affected by loading ...
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... MUX_SELECT pin. Refer to Table 8 for normal operating jumper positions. OUTPUTS The outputs of the AD9238 (and the data clock discussed earlier) are buffered by 74VHC541s (U2, U3, U7, U10) to ensure the correct load on the outputs of the DUT, as well as the extra drive capability to the next part of the system. The 74VHC541s are latches, but on this evaluation board, they are wired and function as buffers ...
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... EVALUATION BOARD BAND-PASS CIRCUITRY FILTERS Figure 39. PCB Test Setup Rev Page JP2 JP3 JP4 JP5 In Out Out Out Out In Out Out Out Out Out In SINE SOURCE LOW JITTER (HP8644) AD9238 CLOCK CIRCUITRY OUTPUT INPUT AD9238 BUFFERS REFERENCE MODE SELECTION/EXTERNAL REFERENCE/CONTROL LOGIC ...
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... RV3299W 10 kΩ 0805 500 Ω 1206 10 kΩ 0805 22 Ω 1206 0 Ω RCA74204 22 Ω SMA200UP DIP06RCUP T1-1T TBLK06REM LOOPTP RED LOOPTP BLK LOOPMINI WHT LOOPMINI RED 64LQFP7X7 AD9238 SOL20 74VHC541 SOIC-8 AD822 SO8NC7 AD8138 TSSOP-14 74VHC04 ...
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... AD9238 LQFP EVALUATION BOARD SCHEMATICS Figure 40. Evaluation Board Schematic Rev Page ...
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... Figure 41. Evaluation Board Schematic (Continued) Rev Page AD9238 ...
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... AD9238 Figure 42. Evaluation Board Schematic (Continued) Rev Page ...
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... RP8 GND 2 RP8 18 3 RP8 RP8 22Ω R39 22Ω Rev Page AD9238 22Ω 22Ω 22Ω 22Ω 22Ω 22Ω 22Ω ...
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... AD9238 LQFP PCB LAYERS Figure 44. PCB Top Side Silkscreen Rev Page ...
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... Figure 45. PCB Top Layer Rev Page AD9238 ...
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... AD9238 Figure 46. PCB Ground Plane Rev Page ...
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... Figure 47. PCB Split Power Plane Rev Page AD9238 ...
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... AD9238 Figure 48. PCB Bottom Layer Rev Page ...
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... Figure 49. PCB Bottom Silkscreen Rev Page AD9238 ...
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... AD9238 DUAL ADC LFCSP PCB The LFCSP PCB requires a low jitter clock source, analog sources, and power supplies. The PCB interfaces directly with Analog Devices standard dual-channel data capture board (HSC-ADC- EVAL-DC), which together with ADI’s ADC Analyzer™ software allows for quick ADC evaluation ...
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... Resistors Resistors Resistors Resistors Resistors Resistors Resistors Resistors Resistors Resistor Resistor Pack Transformers AD9238 SN74LVCH16373A SN74LVC1G04 SN74VCX86 AD8139 Resistors Rev. C| Page AD9238 Package Value 0201 20 pF 0805 10 μF 0402 0.1 μF TAJD 10 μF 0201 0.1 μF Z5.531.3425.0 Wieland 25.602.5453.0 Wieland 0402 36 Ω ...
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... AD9238 LFCSP PCB SCHEMATICS ENCA D7A D7_A 49 D8A D8_A 50 D9A D9_A 51 DRVDD2 52 DRGND2 53 D10A D10_A 54 D11A D11_A 55 D12A D12_A 56 D13A D13_A 57 OTRA OTR_A 58 OEB_A 59 PDWN_A 60 MUX_SEL 61 SH_REF 62 CLK_A 63 VD AVDD5 64 EPAD 65 Figure 50. PCB Schematic ( Rev Page D7_B 32 D7B D6_B ...
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... Figure 51. PCB Schematic ( Rev Page AD9238 ...
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... AD9238 Figure 52. PCB Schematic ( Rev Page ...
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... LFCSP PCB LAYERS Figure 53. PCB Top-Side Silkscreen Rev Page AD9238 ...
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... AD9238 Figure 54. PCB Top-Side Copper Routing Rev Page ...
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... Figure 55. PCB Ground Layer Rev Page AD9238 ...
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... AD9238 Figure 56. PCB Split Power Plane Rev Page ...
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... Figure 57. PCB Bottom-Side Copper Routing Rev Page AD9238 ...
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... AD9238 THERMAL CONSIDERATIONS The AD9238 LFCSP has an integrated heat slug that improves the thermal and electrical properties of the package when locally attached to a ground plane at the PCB. A thermal (filled) via array to a ground plane beneath the part provides a path for heat to escape the package, lowering junction temperature ...
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... Dimensions shown in millimeters Rev Page 9.20 9. 7.20 7.00 SQ TOP VIEW 6.80 (PINS DOWN 0.23 0.18 0.13 0.30 0.25 0.18 PIN 1 64 INDICATOR 1 * 4.85 EXPOSED PAD 4.70 SQ (BOTTOM VIEW) 4. 7.50 REF FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. AD9238 ...
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... AD9238BSTRL-65 –40°C to +85°C AD9238BSTZ-65 –40°C to +85°C AD9238BSTZRL-65 –40°C to +85°C AD9238BCPZ-20 –40°C to +85°C AD9238BCPZRL-20 –40°C to +85°C AD9238BCPZ-40 –40°C to +85°C AD9238BCPZRL-40 –40°C to +85°C AD9238BCPZ-65 –40°C to +85°C AD9238BCPZRL-65 – ...
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... NOTES Rev Page AD9238 ...
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... AD9238 NOTES ©2003–2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D02640–0–11/10(C) Rev Page ...