Proximity Capacitive Touch Sensor Platform

SemtechCorp.'s new platform of capacitive sensing ICs are optimized for thenext-generation of energy-efficient, touch button television applications. The8-channel SX8660/61 touch sensor platform featuresintegrated LED drivers and an extended, 10 cm range of proximity sensing. It isdesigned to replace legacy mechanical button controllers with an analog outputinterface (AOI) that supports the use of a buzzer for audible feedback makingthe platform compatible with television designs.

Thecapacitive analog interface on the SX8660/61 ICs is designed with ananalog-to-digital converter (A dc) that provides sensitivity to work with thickoverlay materials (up to 5 mm) for robust ESD immunity and to support a 10cmrange of proximity detection. With current consumption as low as 70muA atoperation, these ICs help designers meet energy-efficiency eco-regulations fortelevisions.

TheSX8660/61 platform also integrates eight, 256-step LED drivers with individualintensity (linear or logarithmic) fading control that is optimized for humanvision. This allows design of buttons that automatically fade on when touchedand fade off when released with interval speed and initial and final lightintensity levels set by the designer. Special single and continuous breathingmodes are also available.

TheSX8660/61 platform simplifies capacitive touch control design and reducestime-to-market with integrated multi-time programmable firmware that enablesusers to customize various parameters such as scan time, slave address, channelgain and sensitivity thresholds in their applications, without the need for newfirmware development. Additionally, capacitive sense inputs eliminate the needfor external resistors and capacitors, reducing design footprint, bill ofmaterials (BOM) and complexity.

The SX8661 has a preconfigured quick-start mode forapplications requiring proximity sensing and seven buttons, with one AOI andseven LED drivers with PWM fading. The SX8660 is preconfigured with aquick-start mode for applications with eight buttons, two AOIs, one buzzeroutput and five LED drivers with PWM fading. The GPIOs can also be individuallyconfigured for specific application requirements. Both devices feature a smartautomatic offset compensation function that eliminates false triggers due to environmentalfactors such as temperature, humidity and dust. They are offered in a tiny, 4 x4mm 28-QFN package and operate over a -40 to +85C temperature range.