AD7730BRZ-REEL7

Overview

The AD7730BRZ-REEL7 is a CMOS, 24-bit Sigma-Delta analog-to-digital converter (ADC) designed for bridge transducer applications. It features two buffered differential programmable gain inputs and operates from a single +5 V supply. The device accepts unipolar ranges of 0 mV to +10 mV, +20 mV, +40 mV, and +80 mV, as well as bipolar ranges of ±10 mV, ±20 mV, ±40 mV, and ±80 mV. It provides a peak-to-peak resolution of 230,000 counts with an integral nonlinearity of 18 ppm. Key performance metrics include an offset drift of less than 5 nV/°C and a gain drift of less than 2 ppm/°C.

Feature Summary

• 24-bit resolution with 230,000 peak-to-peak counts and 18 ppm maximum integral nonlinearity.
• Two-channel buffered differential programmable gain front end supporting multiple input ranges.
• On-chip 6-bit DAC for offset or TARE voltage removal without external components.
• Low drift specifications: offset drift < 5 nV/°C and gain drift < 2 ppm/°C.

Applications

• Weigh scales
• Pressure measurement systems

Procurement Notes

Verify the package type matches the design requirements, as the AD7730 series is available in 24-pin plastic DIP, SOIC, and TSSOP packages. Confirm that the specific suffix corresponds to the desired packaging format. Ensure the operating temperature range aligns with the industrial specification of -40 °C to +85 °C.

Selection Notes

Select this component for applications requiring high precision with low drift, such as load cells or pressure sensors. The internal chopping mode can be utilized to minimize offset and gain drift over time. Ensure the reference voltage is within the 1 V to 5 V range and compatible with the HIREF bit configuration.

Part Context

The AD7730 is part of Analog Devices' family of complete analog front ends for transducer signal conditioning. It integrates a Sigma-Delta modulator, programmable gain amplifier, and digital filter. The BRZ suffix indicates a lead-free RoHS-compliant version in the SOIC package, while other variants like AD7730L offer different clock specifications.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material.

FAQ

What are the supported analog input ranges?

The device supports four unipolar ranges (0 mV to +10 mV, +20 mV, +40 mV, +80 mV) and four bipolar ranges (±10 mV, ±20 mV, ±40 mV, ±80 mV).

How does the on-chip DAC function?

The 6-bit DAC allows for the removal of TARE voltages by adding or subtracting a programmed voltage from the analog input signal before it reaches the PGA.

What is the purpose of the ACX output pin?

The ACX output provides a signal to control the reversing of bridge excitation polarity in AC-excited bridge applications, aiding in chopper stabilization.