AT42QT1085-AU

Overview

The AT42QT1085-AU is an eight-channel QTouch capacitive touch sensor IC with an integrated haptic engine. It operates on a 2.0 V to 5.5 V supply and features a master/slave SPI interface supporting up to 750 kHz. The device provides eight keys, twelve dedicated GPIO pins, and four additional configurable channels. It utilizes the QTouchADC measurement method with spread spectrum charge transfer for noise immunity. Key specifications include an operating temperature range of -40°C to +85°C and a 32-pin 7x7 mm TQFP package.

Feature Summary

• Integrated haptic engine allows feedback effects triggered by touch detection or host control
• Patented Adjacent Key Suppression technology ensures accurate key detection in close proximity layouts
• Advanced signal processing includes self-calibration, auto drift compensation, and noise filtering
• Spread spectrum operation suppresses external noise and limits RF emissions

Applications

• Consumer electronics requiring tactile feedback integration
• Industrial control panels needing robust noise immunity
• Appliances utilizing glass or plastic overlay interfaces

Procurement Notes

Verify the specific ordering suffix against official Microchip documentation to confirm package type and temperature grade. Ensure compatibility with the required SPI protocol implementation during system design. Confirm availability status as product lifecycles may change without notice.

Selection Notes

Select this component when an integrated solution for both touch sensing and haptic feedback is required. The device supports various electrode materials and panel thicknesses. Consider the available GPIO count and SPI interface speed for system integration requirements.

Part Context

This part belongs to the AT42QT1085 family of QTouch sensor ICs. It is designed for applications requiring multiple touch inputs with enhanced user interaction capabilities through built-in haptic generation. The device simplifies design by eliminating the need for external sampling capacitors.

Replacement Considerations

Consult official Microchip documentation for verified substitute part numbers. Do not assume functional equivalence with other models in the broader sensor category without verifying pinout and protocol compatibility.

FAQ

How does the device handle adjacent key detection?

The AT42QT1085 uses patented Adjacent Key Suppression (AKS) technology to detect the strongest touch delta within a group, ensuring only the intended key is reported.

What is the function of the CHANGE pin?

The CHANGE pin is an open-drain output that asserts low to notify the host microcontroller that a message is waiting to be read via the SPI interface.

Can the device operate without a dedicated voltage regulator?

Yes, the device can tolerate some power supply fluctuations and often operates without a dedicated regulator, provided the supply does not drift quickly.