AD7745ARUZ-REEL

ADCs/DACs - Special Purpose Overview

The AD7745ARUZ-REEL is a single-channel, 24-bit Sigma-Delta capacitance-to-digital converter (CDC) manufactured by Analog Devices Inc. It features an integrated temperature sensor and voltage input channel. The device operates on a single supply from 2.7 V to 5.25 V with a current consumption of 0.7 mA. It provides high resolution down to 4 aF (up to 21 ENOB), accuracy of ±4 fF, and linearity of 0.01%. The part communicates via a 2-wire I²C-compatible serial interface and is housed in a 16-lead TSSOP package.

ADCs/DACs - Special Purpose Feature Summary

• High-resolution capacitance measurement: 24-bit ADC with up to 21 effective bits and ±4 fF absolute accuracy.
• Integrated sensors: On-chip temperature sensor (±2°C accuracy) and differential voltage input channel.
• Flexible excitation: Programmable internal clock oscillator and dual EXC pins for floating capacitive sensors.
• Robust input handling: Tolerates up to 60 pF parasitic capacitance to ground and balances up to 17 pF common-mode capacitance via CAPDAC.

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 REEL suffix indicates tape-and-reel packaging rather than tube packaging when sourcing. Confirm the specific revision level matches design requirements, as specifications are subject to change without notice. Ensure ESD precautions are observed during handling due to the sensitivity of the CMOS inputs.

ADCs/DACs - Special Purpose Selection Notes

Select the AD7745ARUZ-REEL for single-ended or differential floating capacitive sensor interfaces requiring high precision. Use this part instead of the AD7746 if only one capacitance channel is needed. Consider the AD7747 if the sensor has one plate grounded. Verify that the required update rate between 10 Hz and 90 Hz fits the system timing constraints.

ADCs/DACs - Special Purpose Part Context

This component belongs to the AD7745/AD7746 family of specialized data acquisition ADCs designed for capacitive sensing. The AD7745 variant specifically offers a single capacitance input channel, whereas the AD7746 provides two channels. Both share identical electrical characteristics, power requirements, and package dimensions.

ADCs/DACs - Special Purpose Replacement Considerations

Public confirmed substitute part numbers: AD7746ARUZ (Dual-channel equivalent).