EVAL-CN0216-SDPZ Datasheet PDF - Analog Devices

CIRCUIT FUNCTION AND BENEFITS
The circuit in Figure 1 is a precision weigh scale signal conditioning system. It uses the AD7791, a low power buffered 24-bit sigma-delta ADC along with two external ADA4528-1 zero-drift amplifiers. This solution allows for high dc gain with a single supply.

Ultralow noise, low offset voltage, and low drift amplifiers are used at the front end for amplification of the low-level signal from the load cell. The circuit yields 15.3 bit noise-free code resolution for a load cell with a full-scale output of 10 mV.

This circuit allows great flexibility in designing a custom low level signal conditioning front end that gives the user the ability to easily optimize the overall transfer function of the combined sensor-amplifier-converter circuit. The AD7791 maintains good performance over the complete output data range, from 9.5 Hz to 120 Hz, which allows it to be used in weigh scale applications that operate at various low speeds.