AD7794BRU

Overview

The AD7794BRU is a low-power, low-noise analog front end featuring a 24-bit sigma-delta ADC with six differential inputs. It integrates a programmable gain instrumentation amplifier (1 to 128), an internal bandgap reference, and excitation current sources. The device operates on a 2.7 V to 5.25 V supply, consuming 400 μA typical current. It supports output update rates from 4.17 Hz to 470 Hz via a 3-wire serial interface. The B-grade variant functions within a temperature range of −40°C to +105°C in a 24-lead TSSOP package.

Feature Summary

• Integrates a 24-bit sigma-delta ADC with a low-noise programmable gain instrumentation amplifier for direct sensor interfacing.
• Includes an internal bandgap reference and programmable excitation current sources for RTD and bridge sensors.
• Features a low-side power switch to minimize system power consumption by powering down external sensors between conversions.

Applications

• Temperature measurement
• Pressure measurement
• Weigh scales
• Strain gage transducers
• Industrial process control

Procurement Notes

Verify the specific ordering suffix against official documentation to confirm the exact grade and packaging configuration. Confirm that the component meets the required environmental specifications for the intended operating temperature range before finalizing procurement decisions.

Selection Notes

Select this component for high-precision applications requiring multiple differential channels and integrated signal conditioning. Ensure the design accommodates the independent digital and analog supply requirements and utilizes the internal calibration features to maintain specified accuracy levels across the operating temperature range.

Part Context

This part belongs to the AD7794/AD7795 family of complete analog front ends designed for high-precision measurement applications. The AD7794 specifically provides 24-bit resolution, distinguishing it from the 16-bit AD7795 variant within the same series.

Replacement Considerations

Public confirmed substitute: AD7124-8BCPZ.

FAQ

Can the AD7794 operate with separate analog and digital supply voltages?

Yes, the device features independent AVDD and DVDD supplies, both ranging from 2.7 V to 5.25 V, allowing different voltage levels for the analog section and the serial interface.

What is the function of the PSW pin?

The PSW pin acts as a low-side power switch to ground, enabling the user to power down connected bridge sensors between conversions to minimize overall system power consumption.