The device detects a single rapid touch anywhere along the sense elements, or tracks a finger moving along the wheel or slider surface in real time. In both instances, it detects absolute position. The chip can also interface with seven additional touch keys, which can be independently tuned for sensitivity. Target applications include mobile phones, remote controls, small kitchen appliances, home audio, portable media players (including MP3 players) and lighting controls. Electrodes can be any conductive material, which projects sense fields through any dielectric, most commonly plastic or glass. An approaching finger causes a change in the sense field, registering a touch event. Unlike traditional capacitive touch sensors, QT sensors feature automatic self-calibration on power-up. This eliminates long-term drift problems from buildup of contaminants on the touch surface or changing environmental conditions. A low-power mode lets designers optimize the trade-off between response time and power consumption. The chip uses spread-spectrum burst technology to provide better than 20 V/m noise rejection and minimize EMI. It comes in a RoHS-compliant, 32-QFN package and operates from a single 2.8-5-V supply.

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