AT42QT2100-AU

Overview

The AT42QT2100-AU is a QTouch capacitive touch sensor IC manufactured by Microchip Technology. It supports up to seven independent keys and one slider or wheel configuration. The device utilizes patented spread-spectrum charge-transfer technology for robust noise rejection. It operates on a supply voltage ranging from 2.0 V to 5.5 V and communicates via a four-wire SPI interface with a maximum clock rate of 750 kHz. Additional status signals include Data Ready (DRDY) and Change (CHANGE). The component is available in a 32-pin 5 x 5 mm MLF package.

Feature Summary

• Patented spread-spectrum charge-transfer technology provides superior noise immunity and reduced susceptibility to external interference.
• Integrated signal processing includes self-calibration, automatic drift compensation, and hardware-based moisture tolerance.
• Supports Adjacent Key Suppression (AKS) to prevent false triggers from closely spaced electrodes or single-touch events across multiple keys.
• Flexible electrode design allows sensing through dielectric materials such as glass or plastic up to specified thicknesses.

Applications

• Portable electronic devices requiring low-power touch interfaces
• Domestic appliances and audio/video equipment control panels
• PC peripherals and office equipment input controls

Procurement Notes

Verify the specific package variant against project requirements, as the AT42QT2100 series includes both MLF and TQFP options. Confirm that the ordering suffix corresponds to the desired physical footprint. Ensure compatibility with the host system's SPI voltage levels and timing constraints before finalizing procurement.

Selection Notes

Select this component when a dedicated touch controller is needed to offload processing from the main microcontroller. It is suitable for designs requiring up to seven discrete buttons combined with a rotary wheel or linear slider. Consider the power consumption trade-offs between Free Run and Low Power modes based on battery life requirements.

Part Context

This part belongs to the AT42QT2100 family of QTouch sensor controllers. It is designed to replace older resistive touch solutions or complex MCU-based capacitive sensing implementations. The device integrates the necessary analog front-end and digital logic to handle electrode scanning, filtering, and state reporting independently.

Replacement Considerations

Direct pin-compatible replacements within the same package are limited. Review the AT42QT1070 for I2C interface alternatives or the AT42QT1245 for higher channel counts using SPI. Verify firmware compatibility if migrating between different QTouch controller families.