AD9238BSTZRL-20

Overview

The AD9238BSTZRL-20 is a dual-channel, 12-bit analog-to-digital converter (ADC) from Analog Devices. It operates at a maximum sampling rate of 20 MSPS with a single 3 V supply (2.7 V to 3.6 V). The device features dual high-performance sample-and-hold amplifiers and an integrated voltage reference. It utilizes a multistage differential pipelined architecture with output error correction logic to guarantee no missing codes across the full operating temperature range (-40°C to +85°C). The ADC accepts differential or single-ended inputs with selectable spans of 1 V p-p or 2 V p-p. Digital outputs are available in offset binary or two's complement formats via a parallel interface housed in a 64-lead LQFP package.

Feature Summary

• Dual-channel simultaneous sampling with exceptional crosstalk immunity exceeding 85 dB
• Integrated duty cycle stabilizer maintains performance over wide clock variations
• Flexible analog input support for both differential and single-ended configurations
• Multiplexed data output option enables single-port operation from either channel

Applications

• Ultrasound equipment
• Direct conversion or IF sampling receivers
• WB-CDMA, CDMA2000, WiMAX systems
• Battery-powered instruments
• Low cost digital oscilloscopes

Procurement Notes

Verify the specific speed grade suffix matches the required sampling rate. Confirm the package type corresponds to the design footprint. Ensure the ordering code includes the correct environmental and packaging specifications. Cross-reference the datasheet revision to confirm parameter stability. Validate that the component meets all regulatory requirements for the target application.

Selection Notes

Select this model when a 20 MSPS sampling rate is sufficient for the application bandwidth. Consider the power consumption profile relative to higher-speed variants if thermal management is constrained. Evaluate the need for the integrated reference versus external precision references. Assess the system requirement for multiplexed outputs to simplify PCB routing. Verify compatibility with the host processor's parallel interface timing constraints.

Part Context

The AD9238 series offers speed grades of 20 MSPS, 40 MSPS, and 65 MSPS, allowing flexibility between power, cost, and performance. The -20 variant specifically targets applications where lower power consumption is prioritized over maximum throughput. It is pin-compatible with the 14-bit AD9248, facilitating design upgrades without board layout changes.

Replacement Considerations

The AD9238 is pin-compatible with the AD9248. Designers may consider the AD9248 if higher resolution is required without altering the PCB layout. Other speed grades within the AD9238 family offer different performance trade-offs.