ST introduces touch-sensor chips

GENEVA: STMicroelectronics today announced a new family of ultra-low-power touch-sensor chips, following the signing of a technology-licensing agreement with the Korean company ATLab, Inc. The sensors are intended for portable applications such as mobile phones, PDAs, notebook PCs and media players, as well as for the cost-sensitive white-goods market.

The new ‘S-Touch’ family uses ATLab’s capacitive touch-sensing technology, which is based on a fully-digital architecture that needs no on-chip MCU, memory or firmware to implement control interfaces responsive to their users’ touch. The first products in the family are 8-channel and 12-channel devices.

This new hardwired touch-sensor family complements ST’s recently-announced MCU-based ‘QST’ series, which enables intelligent touch-sensitive control interfaces for more complex applications and – at the other end of the scale – in simpler products where the sensor’s MCU can also control multiple secondary functions. The combined sensor portfolio positions ST as the only semiconductor supplier to provide a full range of touch-sensor solutions, meeting a wide spread of requirements and conditions across different industries.

ST has implemented the hardwired finite state machine, at the core of the S-Touch family, in optimized silicon, which requires very little power: consumption is around five to ten times lower than conventional touch-sensor solutions, with a sleep-mode consumption of just 1 microamp. The sensor lines from the device to the application’s touch pads do not need the external RC (resistor-capacitor) networks that are typically required in other solutions, and the sensors themselves are tiny – the 8-input device uses a 2.6 x 1.8mm QFN16 package – ensuring a very compact solution that is some 80% smaller than existing equivalent solutions, and highly cost-competitive.

The sampling time of the sensor, at 2 ms, is also among the fastest in the industry.