AT42QT1244-AU

Overview

The AT42QT1244-AU is a 24-key QMatrix FMEA touch sensor IC from Microchip Technology. It utilizes patented transverse charge-transfer technology with frequency hopping for stable sensing. The device supports up to 24 keys in a matrix layout, featuring individually settable sensitivity via an I2C slave interface operating at speeds up to 400 kHz. It includes self-calibration, auto drift compensation, noise filtering, and Adjacent Key Suppression (AKS). Designed for safety-critical applications, it complies with IEC/EN/UL60730 standards and UL/VDE requirements. Operating voltage ranges from +3 V to 5 V, and the component is housed in a 32-pin 7 × 7 mm TQFP package.

Feature Summary

• Patented transverse charge-transfer sensing technology with frequency hopping capability
• I2C slave interface for key data extraction and individual parameter configuration
• Integrated signal processing including self-calibration, auto drift compensation, and AKS
• FMEA compliant design features with key failure detection and reporting

Applications

• Class B and Class C safety-critical products requiring IEC/EN/UL60730 compliance
• Domestic appliances utilizing plastic, glass, or composite panels
• Touch control interfaces with mixed key sizes and shapes on single-layer PCBs

Procurement Notes

Verify the specific ordering suffix against official documentation to confirm package type and environmental compliance status. Ensure the supplier provides valid traceability documents. Confirm that the component meets RoHS directives as specified in the manufacturer's datasheet. Check for any recent Product Change Notices regarding assembly or material updates before finalizing procurement orders.

Selection Notes

Select this component for designs requiring a high number of touch keys within a matrix configuration. It is suitable for applications needing robust noise immunity through frequency hopping and AKS. Consider the power supply requirements of 3 V to 5 V and the need for a clean LDO regulator. Evaluate panel thickness constraints, which support up to 50 mm glass or 20 mm plastic depending on key size.

Part Context

The AT42QT1244 belongs to the AT42QT1xxx series of capacitance touch sensor ICs by Microchip Technology. It is part of the QMatrix family designed for complex keypad layouts. The AU suffix denotes the 32-pin TQFP package variant. This series integrates advanced signal processing to enable reliable touch detection in electrically noisy environments common in household appliances.

Replacement Considerations

Consult the official Microchip product selector tool for verified cross-references. The AT42QT1245 is a related 24-key device but uses SPI interface and different packaging. Verify pinout compatibility and software register mapping differences when considering alternatives.