AT42QT2120-SU

Overview

The AT42QT2120-SU is a QTouchADC capacitive touch sensor IC manufactured by Microchip Technology, housed in a 20-pin SOIC/TSSOP package. It supports up to 12 keys in communications mode or 5 keys plus discrete outputs in standalone mode. The device operates on a supply voltage of 1.8 V to 5.5 V and features an I2C interface with a fixed slave address of 0x1C. Key signal processing capabilities include self-calibration, auto drift compensation, noise filtering, and Adjacent Key Suppression (AKS). It supports various electrode configurations including buttons, sliders, wheels, proximity sensors, and guard channels.

Feature Summary

• Patented spread-spectrum QTouchADC charge-transfer technology for enhanced noise immunity
• Dual operational modes: Communications mode with I2C configuration and Standalone mode with fixed firmware settings
• Integrated signal processing including self-calibration, drift compensation, and Adjacent Key Suppression
• Supports diverse electrode designs such as spatially interpolated wheels, resistorless sliders, and proximity sensors

Applications

• Consumer electronics requiring wake-on-proximity functionality
• Automotive control interfaces and infotainment systems
• Industrial and medical equipment touch panels
• White goods and black appliances with embedded controls

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to ensure correct package type and temperature range. Confirm that the I2C slave address matches system requirements as it is fixed at 0x1C. Check for any recent Product Change Notifications regarding pinout or electrical specifications before finalizing procurement.

Selection Notes

Select this component when a balance between high channel count and flexible output options is required. Choose Communications mode if dynamic threshold adjustment and AKS configuration via software are necessary. Opt for Standalone mode if minimizing host processor overhead and external component count is prioritized over configurability.

Part Context

The AT42QT2120 belongs to the QTouch family of capacitive sensing controllers from Microchip Technology. It utilizes proprietary QTouchADC acquisition methods to eliminate the need for external sampling capacitors. This series is designed to replace mechanical switches in applications demanding reliability and aesthetic flexibility in panel design.

Replacement Considerations

Direct replacements within the same package and pinout include other variants of the AT42QT2120 family such as the AT42QT2120-XU (TSSOP) or AT42QT2120-MMH (VQFN), provided the package form factor matches the PCB footprint. Verify functional equivalence if substituting with different channel counts like the AT42QT1070.