AT42QT1110-AZ

Overview

The AT42QT1110-AZ is an automotive-grade capacitive touch sensor controller supporting up to 11 QTouch channels. It operates on a 3 V to 5.5 V supply and features spread-spectrum charge-transfer technology for noise immunity. The device supports full-duplex SPI communication at speeds up to 1.5 MHz, alongside discrete detect outputs in 7-key mode. It includes self-calibration, auto drift compensation, and moisture tolerance enhancements. Configuration data is stored in internal EEPROM, allowing stand-alone operation without a host microcontroller.

Feature Summary

• Patented spread-spectrum charge-transfer technology suppresses external noise and RF emissions
• Adjacent Key Suppression (AKS) ensures accurate detection even with closely spaced keys
• Configurable discrete PWM detect outputs enable direct LED indication or status signaling
• Built-in self-test functions verify hardware integrity and operational parameters

Applications

• Automotive radio and infotainment control panels
• Keyless entry systems and door handle interfaces
• Electric window and mirror control switches
• Satellite navigation system user interfaces

Procurement Notes

Verify the specific ordering suffix matches the required package type, as the AT42QT1110 is available in both 32-pin MLF and TQFP formats. Confirm that the -AZ suffix aligns with your automotive qualification requirements. Ensure the selected variant meets the RoHS compliance standards specified in the datasheet. Cross-reference the part number with official Microchip Technology documentation to avoid substitution errors during procurement.

Selection Notes

Select the 11-key configuration for maximum channel density or the 7-key mode if discrete hardware outputs are preferred for simple status indication. Consider panel thickness and material when choosing sample capacitor values, as thicker dielectrics require higher capacitance. Evaluate the need for external SYNC triggering versus internal timed acquisition based on system synchronization requirements. Ensure adequate ESD protection resistors are included in the design to maintain signal integrity.

Part Context

This component belongs to the AT42QT1110 family of QTouch controllers, specifically the automotive-qualified -AZ variant. It shares core functionality with the commercial -MZ version but adheres to stricter automotive reliability standards. The device integrates fully into Microchip's broader capacitive sensing ecosystem, utilizing standard QTouch software libraries for design implementation and tuning.

Replacement Considerations

The AT42QT1110-MZ serves as the commercial equivalent with identical electrical specifications but lacks automotive qualification. No other direct pin-to-pin replacements are documented in the official datasheet. Any alternative selection requires careful verification of interface compatibility, channel count, and package dimensions.