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Touch-panel controller for media device interfaces

Atmel, in the form of its recently-acquired subsidiary formerly known as Quantum Research Group, has introduced a touch controller that combines a “slider” control with buttons, plus an integrated LED controller, and further general-purpose I/O functions. Devices using the company’s chargetransfer technology—this one is in the Q-Touch series–now have Atmel part numbers. This, the AT42QT2160, can control up to 16 individual touch keys with a slider that you can configure to use between two and eight of the touch key channels. If you need an extralong slider control, you can add interpolation between points with a resistive-touch sensor element. In addition, the chip can also control up to 11 LEDs through a PWM output function that is controlled by the host, eliminating the need for an external LED controller. Atmel designed the device for use as a multimedia HMI controller in mobile phones and consumer applications, such as personal media players. It operates from 1.8V to 5.5V and you can also use it in applications such as digital still cameras, PDAs or handheld gaming devices. In common with previous charge-transfer-principle chips, the 2160 claims high immunity to EMI through spread-spectrum modulation and filtering algorithms, calibration of the device over life and designer-defined sensitivity thresholds for individual keys. Adjacent key suppression (AKS) intelligently suppresses signals present from nearby keys so that only intended keys register a touch. The AT42QT2160 has three GPIOs with PWM capability and a further eight shared output ports that provide additional standard outputs for the host without adding cost or using an extra I/O expansion device; you configure the device with an I²C interface. You might design touch button sensor electrodes, of arbitrary size (greater than 6X6 mm) and shape, as copper pads on the printed circuit board or a flexible circuit. The chip will sense touches to those pads through glass or plastic up to 2.5 mm thick.

Samples of the AT42QT2160 are available now in a 28-pin, 4X4 mm QFN package; it will cost $0.98 (10,000). An evaluation board, which comes with an I²C-to-USB converter to connect to a PC, costs $82.50.

Atmel, www.atmel.com