AD7794BRUZ

Overview

The AD7794BRUZ 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. Output data rates range from 4.17 Hz to 470 Hz. It includes a low-side power switch, burnout currents, and a temperature sensor. The B-grade part supports -40°C to +105°C operation 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, programmable excitation current sources, and a low-side power switch for bridge sensors.
• Supports simultaneous 50 Hz/60 Hz rejection and offers multiple serial interface compatibility options.
• Features a built-in temperature sensor and bias voltage generator for simplified system design.

Applications

• Weigh scales
• Industrial process control
• Pressure measurement
• Strain gage transducers
• Gas analysis

Procurement Notes

Verify the specific grade requirements against the datasheet specifications. The B-grade variant covers -40°C to +105°C, while C-grade extends to +125°C. Confirm that the 24-lead TSSOP package aligns with your PCB layout constraints. Ensure supply voltages remain within the 2.7 V to 5.25 V limits for both analog and digital domains.

Selection Notes

Select this component for high-precision applications requiring low noise and low power consumption. The integrated PGA eliminates external amplifiers, reducing board space. Consider the update rate versus noise performance trade-off when configuring the digital filter. Verify compatibility with existing microcontroller serial interfaces before finalizing the design.

Part Context

This component belongs to the AD779x family of complete analog front ends designed for precision measurement. It shares architectural similarities with the AD7795 but provides higher resolution. The series targets industrial and medical instrumentation where signal integrity and power efficiency are critical parameters for system performance.

Replacement Considerations

Public confirmed substitute: AD7124-8BCPZ.

FAQ

Can the AD7794BRUZ operate with an external clock?

Yes, the device can be driven by an external clock via the CLK pin, allowing synchronization with other ADCs or systems.

What is the function of the PSW pin?

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

How does the device handle reference inputs?

It contains an internal bandgap reference and can also accept up to two external differential references applied to REFIN1 and REFIN2 pins.