AD7730BNZ

Overview

The AD7730BNZ is a complete analog front-end for weigh-scale and pressure measurement applications, manufactured by Analog Devices Inc. It features a 24-bit Sigma-Delta ADC with two buffered differential programmable gain inputs and operates from a single +5 V supply. The device accepts low-level transducer signals directly and outputs serial digital words via a three-wire interface compatible with microcontrollers. Key specifications include a peak-to-peak resolution of 230,000 counts, offset drift of 5 nV/°C, and gain drift of 2 ppm/°C. It integrates an on-chip 6-bit DAC for offset removal and supports AC or DC excitation for bridge sensors.

Feature Summary

• 24-bit resolution with 230,000 peak-to-peak counts and no missing codes
• Two-channel buffered differential programmable gain amplifier (PGA)
• On-chip 6-bit DAC for TARE voltage removal
• Three-wire serial interface compatible with SPI and DSPs

Applications

• Weigh scales
• Pressure measurement

Procurement Notes

Verify the package type matches the 'BNZ' suffix, which indicates a 24-pin plastic DIP. Confirm the revision level against the latest Analog Devices datasheet to ensure parameter accuracy. Check for RoHS compliance status as manufacturing processes may evolve. Ensure the operating temperature range meets the application requirements of -40°C to +85°C.

Selection Notes

Select the AD7730BNZ for applications requiring high precision in low-frequency signal acquisition. It is suitable for interfacing directly with strain gauges and load cells without external amplification. Consider the power consumption differences between normal and standby modes if battery operation is required. Verify that the system calibration capabilities meet the long-term stability needs of the design.

Part Context

The AD7730 is part of Analog Devices' family of precision Sigma-Delta ADCs designed for industrial process control and sensor interfaces. The 'B' version specifies the industrial temperature range (-40°C to +85°C). The 'N' suffix denotes a lead-free, non-halogenated plastic DIP package compliant with environmental standards. This component serves as a direct replacement for older discrete amplifier and ADC solutions in high-accuracy measurement systems.

Replacement Considerations

Direct pin-compatible replacements within the same package are limited due to specific feature sets. Evaluate the AD7731 for multi-channel process control applications or the AD7792 for lower power requirements. Ensure any substitute supports the required 24-bit resolution and PGA functionality.