AD7731BR-REEL

Overview

The AD7731BR-REEL is a complete analog front-end for process control applications, featuring a 24-bit sigma-delta ADC architecture. It includes a proprietary programmable gain front end accepting low-level signals directly from transducers. The device offers three buffered differential inputs configurable as five pseudo-differential inputs and supports seven unipolar and bipolar ranges from ±20 mV to ±1.28 V. It achieves 16 bits peak-to-peak resolution at an 800 Hz output rate with programmable rates up to 6.4 kHz. Operating on a single +5 V supply, it features self-calibration, offset drift under 5 nV/°C, and a serial interface compatible with microcontrollers.

Feature Summary

• Proprietary programmable gain front end accepts low-level signals directly from transducers without external conditioning.
• Sigma-delta architecture with a low-pass programmable digital filter allows adjustment of filter cutoff, output rate, and settling time.
• Includes self-calibration and system calibration options to maintain high accuracy with minimal drift.
• Features FASTStep mode for rapid channel sequencing with fast settling times during input transitions.

Applications

• Process Control Systems
• PLCs and DCS
• Industrial Instrumentation

Procurement Notes

Verify the specific reel packaging configuration against the datasheet ordering guide. Confirm that the B version temperature range meets industrial requirements. Ensure the RoHS compliance status aligns with project specifications, noting that non-Z suffixes may not be compliant. Validate pin compatibility with the target PCB footprint before finalizing procurement.

Selection Notes

Select this component when a complete analog front-end solution is required for process control. It is suitable for applications needing direct connection to transducers with varying signal levels. Consider the programmable gain and filtering capabilities for noise reduction. Verify that the serial interface timing matches the host controller's capabilities.

Part Context

The AD7731 series by Analog Devices provides integrated signal chain solutions for precision measurement. This part combines a sigma-delta modulator, programmable gain amplifier, and digital filter in a single package. It is designed to simplify the design of high-accuracy data acquisition systems used in industrial environments.

Replacement Considerations

Direct replacements include AD7731BRZ and AD7731BRU. Check RoHS compliance if environmental regulations require lead-free components. Verify package dimensions for SOIC vs TSSOP compatibility. Ensure electrical specifications match the original design requirements.

FAQ

How many analog input channels does the AD7731 support?

The device supports three fully differential inputs (AIN1-AIN2, AIN3-AIN4, AIN5-AIN6) which can be configured as five pseudo-differential inputs using AIN6 as a common reference.

What is the maximum output update rate?

The programmable output rate can be adjusted up to 6.4 kHz, depending on the selected filter settings and chopping mode.

Does the AD7731 have internal calibration capabilities?

Yes, it features both self-calibration and system calibration options to minimize offset and gain errors over time and temperature.