Features and Benefits
- Integrated dual 12-bit ADC
- Single 3 V supply operation (2.7 V to 3.6 V)
- SNR = 70 dB (to Nyquist, AD9238-65)
- SFDR = 80.5 dBc (to Nyquist, AD9238-65)
- Low power: 300 mW/channel at 65 MSPS
- Differential input with 500 MHz, 3 dB bandwidth
- Exceptional crosstalk immunity > 85 dB
- Flexible analog input: 1 V p-p to 2 V p-p range
- Offset binary or twos complement data format
- Clock duty cycle stabilizer
- Output datamux option
The AD9238 is a dual, 3 V, 12-bit, 20/40/65 MSPS analog to digital converter. It features dual high performance sample-and-hold amplifiers and an integrated voltage reference. The AD9238 uses a multistage differential pipelined architecture with output error correction logic to provide 12-bit accuracy and guarantee no missing codes over the full operating temperature range at up to 65 MSPS data rates.
The wide bandwidth, differential SHA allows for a variety of user-selectable input ranges and offsets including single-ended applications. It is suitable for various applications including multiplexed systems that switch full-scale voltage levels in successive channels and for sampling inputs at frequencies well beyond the Nyquist rate. The AD9238 is suitable for applications in communications, imaging and medical ultrasound.
Dual single-ended independent clock inputs are used to control all internal conversion cycles. A Duty Cycle Stabilizer (DCS) is available on the AD9238-65 and can compensate for wide variations in the clock duty cycle, allowing the converters to maintain excellent performance. The digital output data is presented in either straight binary or twos complement format. Out-of-range signals indicate an overflow condition, which can be used with the most significant bit to determine low or high overflow.
Fabricated on an advanced CMOS process, the AD9238 is available in either a space saving 64-pin LQFP or 64-pin LF-CSP and is specified over the industrial temperature range (-40°C to +85°C).
- Pin-compatible with the AD9248, 14-bit 20MSPS/ 40 MSPS/65 MSPS ADC.
- Speed grade options of 20 MSPS, 40 MSPS, and 65 MSPS allow flexibility between power, cost, and performance to suit an application.
- Low power consumption: AD9238-65: 65 MSPS = 600 mW, AD9238-40: 40 MSPS = 330 mW, and AD9238-20: 20 MSPS = 180 mW.
- Typical channel isolation of 85 dB at fIN = 10 MHz.
- The clock duty cycle stabilizer (AD9238-20/AD9238-40/ AD9238-65) maintains performance over a wide range of clock duty cycles.
- Multiplexed data output option enables single-port operation from either Data Port A or Data Port B.
- Ultrasound equipment
- Direct conversion or IF sampling receivers
- WB-CDMA, CDMA2000, WiMAX
- Battery-powered instruments
- Hand-held scopemeters
- Low cost, digital oscilloscopes
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Documentation & Resources
AN-905: VisualAnalog™ Converter Evaluation Tool Version 1.0 User Manual8/18/2020
AN-835: Understanding High Speed ADC Testing and Evaluation (Rev. B)5/12/2015
AN-501: Aperture Uncertainty and ADC System Performance (Rev. A)2/14/2015
AN-282: Fundamentals of Sampled Data Systems2/14/2015
AN-756: Sampled Systems and the Effects of Clock Phase Noise and Jitter (Rev. 0)2/14/2015
AN-827: A Resonant Approach to Interfacing Amplifiers to Switched-Capacitor ADCs (Rev. 0)2/14/2015
AN-935: Designing an ADC Transformer-Coupled Front End (Rev. 0)2/14/2015
AN-742: Frequency Domain Response of Switched-Capacitor ADCs (Rev. C)2/14/2015
AN-345: Grounding for Low-and-High-Frequency Circuits2/14/2015
AN-1142: Techniques for High Speed ADC PCB Layout (Rev. 0)2/2/2012
AN-737: How ADIsimADC Models an ADC (Rev. B)11/9/2007
AN-807: Multicarrier WCDMA Feasibility (Rev. 0)11/9/2007
AN-808: Multicarrier CDMA2000 Feasibility (Rev. 0)11/9/2007
AN-803: Pin Compatible High Speed ADCs Simplify Design Tasks (Rev. 0)11/29/2006
AN-715: A First Approach to IBIS Models: What They Are and How They Are Generated (Rev. 0)12/14/2004
AN-741: Little Known Characteristics of Phase Noise (Rev. 0)11/29/2004
AN-297: Test Video A/D Converters Under Dynamic Conditions9/6/2002
Designing Power Supplies for High Speed ADC2/1/2012
Matching An ADC To A Transformer7/13/2007
Wideband A/D Converter Front-End Design Considerations: When to Use a Double Transformer Configuration7/1/2006 Analog Dialogue
Correlating High-Speed ADC Performance to Multicarrier 3G Requirements6/1/2003
DNL and Some of its Effects on Converter Performance6/1/2001
Tools & Simulations
Virtual Eval - BETA
Virtual Eval is a web application to assist designers in product evaluation of ADCs, DACs, and other ADI products. Using detailed models on Analog’s servers, Virtual Eval simulates crucial part performance characteristics within seconds. Configure operating conditions such as input tones and external jitter, as well as device features like gain or digital down-conversion. Performance characteristics include noise, distortion, and resolution, FFTs, timing diagrams, response plots, and more.
AD9238 IBIS Models
For designers who are selecting or evaluating high speed ADCs, VisualAnalog™ is a software package that combines a powerful set of simulation and data analysis tools with a user-friendly graphical interface.
AD9238 Companion Parts
Recommended ADC Drivers
Recommended Clock Drivers
Recommended External Reference
- For improved thermal drift and gain accuracy: ADR130.
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