AT42QT2640-AU

Overview

The AT42QT2640-AU is a digital burst-mode capacitive touch sensor IC designed for QMatrix layouts. It supports up to 64 keys and eight sliders or wheels with 8-bit resolution. The device utilizes patented transverse charge-transfer technology with frequency hopping. It operates on a 4.75 V to 5.25 V supply and features an SPI slave interface with a maximum clock of 4 MHz. The component is housed in a 44-pin, 10 × 10 mm TQFP package.

Feature Summary

• Supports FMEA and IEC/EN/UL60730 compliance with key failure detection
• Includes self-calibration, auto drift compensation, and noise filtering
• Features Adjacent Key Suppression (AKS) technology
• Allows individually settable key sensitivity via serial interface

Applications

• Class B and Class C safety-critical products
• Domestic appliances requiring FMEA compliance
• Touch panels with mixed key, slider, and wheel configurations

Procurement Notes

Verify the specific ordering suffix against official Microchip documentation to confirm package type and environmental compliance. Ensure the host system provides a clean power supply via a dedicated LDO regulator to maintain analog reference stability. Confirm that the design includes necessary external components such as the 16 MHz oscillator and matrix resistors.

Selection Notes

Select this IC for applications requiring high channel counts and robust noise immunity under thick panels. It is suitable for designs needing FMEA analysis support and independent key parameter configuration. Consider the 44-pin TQFP footprint and 16 MHz crystal requirements during PCB layout planning.

Part Context

This component belongs to the AT42QT2xxx series of capacitive touch sensors from Microchip Technology. It is part of the QMatrix family, which uses transverse charge-transfer sensing to detect touches across a grid of electrodes. The series is designed for stable operation in electrically noisy environments.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided source material.