AT42QT1244-MU

Overview

The AT42QT1244-MU 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 under varying conditions. The device supports up to 24 keys with individually settable sensitivity via an I2C slave interface operating at speeds up to 400 kHz. Key features include self-calibration, auto drift compensation, noise filtering, and Adjacent Key Suppression (AKS). It complies with FMEA and IEC/EN/UL60730 safety standards, offering UL approval and VDE compliance for class B and C safety-critical products. Power supply ranges from +3 V to 5 V, and it is available in a 32-pin 7 × 7 mm TQFP package.

Feature Summary

• Supports up to 24 keys using patented transverse charge-transfer technology with frequency hopping
• Includes self-calibration, auto drift compensation, noise filtering, and Adjacent Key Suppression (AKS)
• Complies with FMEA and IEC/EN/UL60730 safety standards for class B and C applications
• Features an I2C slave interface for key data extraction and individual parameter setup

Applications

• Safety-critical domestic appliances requiring FMEA compliance
• Industrial control panels needing robust noise immunity and AKS
• Consumer electronics 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 tape/reel specifications. Ensure compatibility with your system's I2C voltage levels and power supply requirements. Check for any recent product change notices that might affect pinout or electrical characteristics before finalizing procurement.

Selection Notes

Select this component when a high number of touch keys (up to 24) are required in a matrix configuration. It is suitable for designs demanding strict safety compliance (FMEA, IEC/60730) and robust performance in noisy environments. Consider the TQFP package if through-hole or larger surface-mount footprint is preferred over QFN.

Part Context

The AT42QT1244 belongs to Microchip's QTouch family of capacitive touch sensor ICs. It is specifically designed for matrix layouts, allowing flexible electrode designs including two-part shapes and various materials like PCB, FPCB, and ITO. The device integrates all necessary signal processing functions, minimizing external component count and enabling cost-effective single-sided PCB implementations.

Replacement Considerations

Check Microchip's official cross-reference tools for direct replacements. Ensure any substitute maintains the same channel count, interface type, and safety certifications if used in critical applications.