AD7730BN

Overview

The AD7730BN is a 24-bit Sigma-Delta analog-to-digital converter (ADC) designed for weigh scale and pressure measurement applications. It features two buffered differential programmable gain amplifier (PGA) inputs with gains up to 128, supporting unipolar ranges of 0–80 mV and bipolar ranges of ±80 mV. The device integrates a 6-bit DAC for offset removal, a programmable digital filter, and an on-chip clock oscillator. Operating from a single +5 V supply, it achieves a peak-to-peak resolution of 230,000 counts with an offset drift of 5 nV/°C and gain drift of 2 ppm/°C. It communicates via a three-wire serial interface compatible with microcontrollers.

Feature Summary

• 24-bit resolution with no missing codes and 230,000 peak-to-peak counts
• Two-channel buffered differential PGA with gains from 1 to 128
• Integrated 6-bit DAC for TARE voltage removal
• Programmable digital filter with FastStep mode for rapid settling

Applications

• Weigh scales
• Pressure measurement transducers

Procurement Notes

Verify the suffix 'BN' against the official datasheet pinout and package options. The document specifies availability in 24-pin plastic DIP, 24-lead SOIC, and 24-lead TSSOP packages. Confirm that the specific ordering code matches one of these physical form factors before procurement.

Selection Notes

Select this component for high-precision bridge sensor interfaces requiring low drift. Ensure the application supports a single +5 V analog supply and a 2.7 V to 5.25 V digital supply. Verify that the required output data rates align with the programmable filter settings and master clock frequency of 4.9152 MHz.

Part Context

The AD7730 is part of Analog Devices' precision ADC portfolio, specifically optimized for industrial sensors. It serves as a complete analog front end, eliminating the need for external amplifiers or reference circuits in many weigh scale designs. The B version denotes the industrial temperature range specification.

Replacement Considerations

The AD7730L is a related variant within the same family. While functionally similar, it operates at a different specified clock frequency (2.4576 MHz vs. 4.9152 MHz). Verify timing requirements when substituting.