Single-Key Capacitive Touch Controllers Fit Portable Devices
The AT42QT101X family of single-key touch controllers from Atmel offers power consumption below 17 µA for next-generation portable touch devices for longer battery life (see the figure). Based on Atmel’s patented QTouch capacitive touch technology for buttons, wheels, and sliders, these controllers also offer a better response time, according to the company. This allows devices to “wake up” faster than products currently on the market, Atmel says. When they detect a touch, these devices temporarily switch to a 12.6-ms fast response mode, allowing additional touches to be detected quickly.
Like Atmel’s other touch technology devices, the AT42QT101X family uses spread-spectrum modulation for excellent electromagnetic compatibility (EMC), the company says. The ICs automatically calibrate when they’re powered up. The controllers also will stay calibrated, even with moisture buildup or other contaminants on the touch surface. With these controllers, the touch surface remains reliable throughout its lifetime as well.
The AT42QT1010 includes a timer to reset a “stuck key” condition after 60 seconds, while the AT42QT1011 indicates a touch condition while the sensor is in “in detect” mode but does not have a timeout. The AT42QT1012 includes a touch-on/touch-off or “toggle” key and includes a configurable power-down timer, preventing devices from inadvertently being left on.
Key sensitivity on all devices can be configured for different panel thickness and materials. Electrodes can be made from any conductive material, including transparent indium tin oxide (ITO). There are few constraints on the key shape or size, providing a great level of flexibility in the industrial design, Atmel says. The IC also can be configured for use as a proximity sensor, detecting nearby hands or objects. This functionality is typically used to illuminate “hidden until lit” keys when a hand or finger approaches the device.
The AT42QT101X devices are available now. Prices start at $0.20 in high volumes. Evaluation kits also are available.
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© 2013 Penton Media Inc.
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