EVK1040A: 4 Button Capacitive Touch, 1.8 ~ 5.5V in

This kit is for the evaluation and development of applications using the AT42QT1040-MMH ('QT1040') 4 Channel QTouch™ Integrated Circuit (IC). In this example, the QT1040 is shown working on a simple battery powered double-sided PCB. The EVK1040A is configured with 4 capacitive keys behind a 1mm acrylic front panel, where a touch is shown by an LED for each key touched.

About the IC:

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

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

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