AD7731BRUZ

Overview

The AD7731BRUZ is a complete analog front-end for process control applications, featuring a proprietary programmable gain front end that accepts low-level signals directly from transducers. It utilizes a sigma-delta architecture with an analog modulator and a low-pass programmable digital filter to adjust cutoff frequency, output rate, and settling time. The device includes three buffered differential programmable gain analog inputs configurable as five pseudo-differential inputs, alongside a differential reference input. Operating from a single +5 V supply, it supports seven unipolar ranges (0 to +20 mV up to +1.28 V) and seven bipolar ranges (±20 mV up to ±1.28 V). Peak-to-peak resolution reaches 16 bits at an 800 Hz output rate, with channel switching in 1 ms maintaining 13-bit performance.

Feature Summary

• Features a programmable gain front end capable of accepting a wide range of input signal levels directly from transducers without external amplification.
• Incorporates a sigma-delta architecture with a programmable digital filter allowing adjustment of filter cutoff, output rate, and settling time.
• Includes self-calibration and system calibration options to maintain high accuracy with minimal offset and gain drift over temperature and time.
• Supports FASTStep mode for optimized channel sequencing, reducing settling time during transitions between different input channels.

Applications

• Process Control Systems
• Programmable Logic Controllers (PLCs)
• Distributed Control Systems (DCS)
• Industrial Instrumentation

Procurement Notes

Verify the specific package variant when ordering, as the BRU suffix denotes the 24-lead TSSOP package. Confirm RoHS compliance status if required by your manufacturing standards, noting that the Z suffix indicates RoHS compliance while non-Z variants may not be compliant. Ensure the operating temperature range aligns with industrial specifications (-40°C to +85°C). Cross-reference the datasheet revision to confirm pinout and electrical characteristics match your design requirements before finalizing procurement.

Selection Notes

Select the AD7731BRUZ when a complete analog front-end solution is needed for process control applications requiring high precision. Consider this component if your design demands multiple differential or pseudo-differential inputs with programmable gain. Evaluate the need for internal calibration features to minimize external component count. Ensure the serial interface compatibility matches your microcontroller or DSP architecture, particularly regarding clock polarity and data format requirements.

Part Context

The AD7731 belongs to Analog Devices' family of 24-bit sigma-delta ADCs designed for high-precision measurement. It serves as a dedicated analog front-end, integrating the modulator, programmable gain amplifier, and digital filter into a single chip. This integration simplifies the design of industrial measurement systems by reducing the number of external components required for signal conditioning and conversion compared to discrete solutions.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Verify pinout and electrical specifications carefully if considering alternative ADCs from other manufacturers, as interface timing and register configurations may differ significantly.