Touch-Sensing Controllers Eliminate Mechanical Buttons/Switches

Designed to detect the presence of objects without relying on physical contact, the MPR083 and MPR084 capacitive touch-sensor controllers can replace mechanical knobs and push buttons. The MPR083 targets 8-position rotary interface applications, and the MPR084 8-point touch-panel applications. Both controllers have a common pin-out, which simplifies management of control panels, switch replacements, rotary and linear sliders, and touch-pad implementations. They use a digital output I2C interface for system communications. The controllers run on 1.8V to 3.6V, drawing 150 µA average supply current with all touch pads being monitored and 1 µA standby current. They include proprietary false-touch rejection technology and come in 16-pin QFN and TSSOP packages. The company also offers complimentary proximity-sensing software designed to run on all of its eight-bit S08 and 32-bit ColdFire V1 microcontrollers, encompassing hundreds of device options. The software provides a cost-effective, source-code solution for design engineers who want to integrate touch sensing for up to 32 electrodes into existing S08 or ColdFire V1 MCU designs. Price for either controller is $1.07 each/10,000. Complimentary touch-sensing software for the S08 and ColdFire V1 MCUs is downloadable at the web site. FREESCALE SEMICONDUCTOR INC., Austin, TX. (800) 521-6274.