AD7731BRU-REEL7

Overview

The AD7731BRU-REEL7 is a 24-bit sigma-delta analog-to-digital converter (ADC) in a 24-lead TSSOP package. It features three buffered differential programmable gain inputs, configurable as five pseudo-differential channels. The device operates from a single +5 V analog supply and a digital supply ranging from 2.7 V to 5.25 V. It supports output update rates up to 6.4 kHz with a peak-to-peak resolution of 16 bits at 800 Hz. Key static performance metrics include an integral nonlinearity of 15 ppm of full-scale range and an offset drift of less than 5 nV/°C.

Feature Summary

• Features a proprietary programmable gain front end accepting various low-level transducer signals directly.
• Includes a two-stage digital filter allowing adjustment of cutoff frequency, output rate, and settling time.
• Supports self-calibration and system calibration options to minimize offset and gain errors.

Applications

• Process control systems
• Programmable Logic Controllers (PLCs)
• Distributed Control Systems (DCS)
• Industrial instrumentation

Procurement Notes

Verify the specific ordering suffix REEL7 corresponds to the tape-and-reel packaging format for the TSSOP variant. Confirm that the B version meets the required industrial temperature range specifications. Ensure compatibility with the intended serial interface configuration before finalizing procurement orders.

Selection Notes

Select this component when a complete analog front-end solution is required for process control applications. It is suitable for designs needing multiple differential inputs with high precision and low drift characteristics. Consider the available input ranges and the necessity for internal calibration features during the design phase.

Part Context

The AD7731 belongs to Analog Devices' family of low-noise, high-throughput 24-bit sigma-delta ADCs. It is designed specifically as a complete analog front-end for process control applications, integrating a programmable gain amplifier, multiplexer, and sigma-delta modulator into a single monolithic device.

Replacement Considerations

The AD7731BRZ is a RoHS-compliant alternative in the same SOIC package. For TSSOP packages, the AD7731BRUZ serves as the lead-free equivalent. Verify pinout and electrical specifications match before substitution.

FAQ

Can the AD7731 operate with an external clock source?

Yes, the MCLK IN pin can be driven by a CMOS-compatible clock signal, or a crystal/resonator can be connected between MCLK IN and MCLK OUT.

What is the function of the FASTStep mode?

FASTStep mode allows the second stage filtering to be performed by a specialized filter until the output has fully settled after detecting a step input on the channel.

How many analog input channels are available?

The device provides three buffered differential programmable gain analog inputs, which can be configured as five pseudo-differential inputs using AIN6 as a common reference.