The AT42QT1040 (QT1040) is a digital burst mode charge-transfer (QT™) capacitive sensor driver designed for touch-key applications. The device can sense from one to four keys; one to three keys can be disabled by not installing their respective sense capacitors. Any of the four channels can be disabled in this way.

The device includes all signal processing functions necessary to provide stable sensing under a wide variety of changing conditions, and the outputs are fully de-bounced. Only a few external parts are required for operation.

The QT1040 modulates its bursts in a spread-spectrum fashion in order to heavily suppress the effects of external noise, and to suppress RF emissions.

Features:

• Number of QTouch® Keys: Up to four
• Discrete Outputs: Four discrete outputs indicating individual key touch
• Technology: Patented spread-spectrum charge-transfer (direct mode)
• Electrode Design: Simple self-capacitance style (refer to the Touch Sensors Design Guide)
• Electrode Materials: Etched copper, silver, carbon, Indium Tin Oxide (ITO)
• Electrode Substrates: PCB, FPCB, plastic films, glass
• Panel Materials: Plastic, glass, composites, painted surfaces (low particle density metallic paints possible)
• Panel Thickness: Up to 10 mm glass, 5 mm plastic (electrode size dependent)
• Key Sensitivity: Fixed key threshold, sensitivity adjusted via sample capacitor value
• Adjacent Key Suppression Patented Adjacent Key Suppression® (AKS®) technology to enable accurate key detection
• Interface: Pin-per-key outputs, plus debug mode to observe sensor signals
• Moisture Tolerance: Increased moisture tolerance based on hardware design and firmware tuning
• Signal Processing: Self-calibration, auto drift compensation, noise filtering
• Applications: Mobile, consumer, white goods, toys, kiosks, POS, and so on
• Power: 1.8 V – 5.5 V
• Package: 20-pin 3 x 3 mm VQFN RoHS compliant

Package: QFN20

Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-9524-AT42-QTouch-BSW-AT42QT1040_Datasheet.pdf