AD9235BRU-20

Overview

The AD9235BRU-20 is a monolithic, single-supply, 12-bit analog-to-digital converter (ADC) operating at a maximum sampling rate of 20 MSPS. It utilizes a multistage differential pipelined architecture with output error correction logic to ensure no missing codes across the full industrial temperature range (-40°C to +85°C). The device features an on-chip high-performance sample-and-hold amplifier (SHA) and voltage reference, powered by a single 3 V supply (2.7 V to 3.6 V). It accepts differential or single-ended analog inputs with a flexible input span ranging from 1 V p-p to 2 V p-p. Digital outputs are available in offset binary or two's complement formats via a parallel interface housed in a 28-lead TSSOP package.

Feature Summary

• Multistage differential pipelined architecture with output error correction logic for guaranteed linearity
• Integrated high-performance sample-and-hold amplifier (SHA) and internal voltage reference
• Flexible analog input configuration supporting both differential and single-ended modes
• On-chip clock duty cycle stabilizer to maintain performance under varying clock conditions

Applications

• Ultrasound equipment
• IF sampling in communications receivers
• Battery-powered instruments
• Hand-held scopemeters
• Low cost digital oscilloscopes

Procurement Notes

Verify the specific suffix 'RU' corresponds to the 28-lead TSSOP package when sourcing replacements. Confirm that the '-20' designation strictly indicates the 20 MSPS speed grade, as higher speed variants share the same pinout but differ in timing parameters. Ensure power supply decoupling meets the datasheet requirements for AVDD and DRVDD pins to maintain specified SNR and SFDR performance levels.

Selection Notes

Select this component when a 12-bit resolution and 20 MSPS throughput are required within a single 3 V supply system. Consider the AD9235 family if pin compatibility with the AD9214-65 is needed for simplified upgrades from 10-bit systems. Evaluate the internal reference accuracy against external reference needs, noting that the internal reference offers ±35 mV error which may impact total system accuracy in precision applications.

Part Context

The AD9235BRU-20 belongs to the AD9235 family of 12-bit ADCs, which also includes -40 and -65 speed grades. All variants share identical pinouts and architectural features, differing primarily in maximum sampling rates and associated AC performance metrics like SNR and SFDR. The BRU suffix denotes the industrial temperature range and TSSOP packaging, distinguishing it from military or LFCSP packaged versions.

Replacement Considerations

AD9235BRUZ-20

FAQ

Does the AD9235BRU-20 support single-ended input configurations?

Yes, the wide bandwidth, truly differential SHA allows user-selectable input ranges and offsets, including single-ended applications.

What is the pipeline latency of the AD9235BRU-20?

The AD9235 has a fixed pipeline delay (latency) of 7 cycles.

How does the device handle out-of-range signals?

An Out-of-Range (OTR) signal indicates an overflow condition, which can be used with the most significant bit to determine whether the overflow is low or high.