AD7151BRMZ-REEL

Overview

The AD7151BRMZ-REEL is a single-channel capacitance-to-digital converter (CDC) designed for proximity sensing applications. It operates on a 2.7 V to 3.6 V supply with a typical current consumption of 70 μA. The device features a sigma-delta architecture with a conversion time of 10 ms and supports input ranges from 0.4 pF to 4 pF, achieving resolutions down to 1.0 fF. It includes an internal excitation source at approximately 16 kHz and integrates adaptive thresholding for environmental compensation. Communication is handled via a 2-wire I²C-compatible serial interface operating up to 400 kHz.

Feature Summary

• Integrates adaptive threshold algorithm to compensate for slow environmental variations such as humidity and temperature changes.
• Features ultra-low power consumption suitable for battery-operated devices with automatic power-down timer functionality.
• Includes programmable CAPDAC to offset large sensor capacitances and maintain optimal operating range.
• Provides flexible comparator modes including fixed threshold, positive/negative change detection, and window comparison.

Applications

• Proximity sensing
• Contactless switching
• Position detection

Procurement Notes

Verify the REEL suffix indicates tape-and-reel packaging rather than tube packaging when sourcing components. Confirm that the specific lot date code meets project requirements. Ensure ESD precautions are observed during handling due to the sensitivity of the capacitive input pins. Cross-reference the ordering information with the manufacturer's latest datasheet to confirm availability status.

Selection Notes

Select this component over the AD7150 if only a single capacitive channel is required for the application. Consider the AD7150 if dual-channel measurement capability is necessary. Evaluate the need for the adaptive threshold feature versus fixed threshold settings based on the stability of the sensor environment. Ensure the system voltage remains within the 2.7 V to 3.6 V operational range.

Part Context

The AD7151 is part of Analog Devices' specialized capacitance-to-digital converter family. It serves as the single-channel counterpart to the AD7150, which offers two channels. Both devices share similar core technologies, including sigma-delta modulation and adaptive thresholding, but differ in channel count and pin configuration.

Replacement Considerations

The AD7150BRMZ is a functional alternative requiring software adaptation for dual-channel operation. Verify pin compatibility and register mapping differences before substitution. No other direct single-channel replacements are documented in the provided specifications.