AD7745ARUZ-REEL7

ADCs/DACs - Special Purpose Overview

The AD7745ARUZ-REEL7 is a high-resolution, sigma-delta capacitance-to-digital converter (CDC) manufactured by Analog Devices Inc. It features a single capacitance input channel with 24-bit resolution and up to 21 effective bits of resolution. The device converts capacitance directly to digital data with an accuracy of ±4 fF and linearity of ±0.01%. It operates on a single supply voltage ranging from 2.7 V to 5.25 V, consuming approximately 0.7 mA. Key specifications include a full-scale range of ±4 pF, tolerance for up to 60 pF of parasitic capacitance to ground, and simultaneous 50 Hz/60 Hz rejection at 16 Hz update rates.

ADCs/DACs - Special Purpose Feature Summary

• 24-bit Sigma-Delta Capacitance-to-Digital Converter with 4 aF resolution
• Integrated internal clock oscillator and voltage reference
• On-chip temperature sensor with 0.1°C resolution and ±2°C accuracy
• I2C-compatible 2-wire serial interface

ADCs/DACs - Special Purpose Applications

• Pressure measurement systems
• Position sensing applications
• Level sensing and flowmeters
• Humidity sensing and impurity detection

ADCs/DACs - Special Purpose Procurement Notes

Verify the REEL7 suffix indicates tape-and-reel packaging when sourcing components. Confirm that the specific lot matches the required automotive temperature grade (-40°C to +125°C). Ensure the ordering documentation explicitly lists the AD7745ARUZ part number to avoid confusion with the dual-channel AD7746 variant.

ADCs/DACs - Special Purpose Selection Notes

Select the AD7745ARUZ for single-ended or differential floating capacitive sensor interfaces requiring one measurement channel. Choose this component over the AD7746 if only one capacitance input is needed. Ensure the application supports the 16-lead TSSOP package dimensions and provides adequate decoupling for the 2.7 V to 5.25 V supply range.

ADCs/DACs - Special Purpose Part Context

This component belongs to the AD7745/AD7746 family of precision capacitance-to-digital converters. The AD7745 variant specifically provides a single capacitance input channel, whereas the AD7746 offers two channels. Both share identical architecture, including the sigma-delta modulator, digital filter, and excitation sources, but differ in pin count allocation for the second channel inputs.

ADCs/DACs - Special Purpose Replacement Considerations

The AD7746ARUZ serves as a functional substitute if a second capacitance channel is required, though it occupies the same footprint. For grounded plate sensors, the AD7747 is recommended instead. Verify that any replacement maintains the I2C address compatibility and register map structure.