Ultra-low-power capacitive sensor and touch sensing software suite

CAMBRIDGE, UK — Freescale expands its intelligent touch sensing offering with the MPR121 ultra-low-power capacitive sensor and a touch sensing software suite compatible with more than 300 of the company 8-bit MCUs.

Manufacturers are rapidly migrating from resistive to capacitive touch technology to answer the demand for intuitive user interfaces that enhance interactivity and improve end-product functionality.

Touch sensing technology boosts reliability by eliminating mechanical wear and tear. In addition, user interface controllers can manage multiple configurations and provide greater flexibility, helping reduce overall system cost.
Freescale’s second-generation MPR121 capacitive touch sensor provides highly reliable touch detection through increased electrode count and integration of automatic calibration and area detection systems.

The 12-pad touch sensor is available in the industry’s smallest lead-free package claims the company, and offers the lowest power consumption at 29 microA average supply current, helping OEMs meet aggressive power targets.
The touch sensing software suite provides an alternate solution by enabling the integration of touch sensing functionality into applications based on Freescale 8-bit MCUs. The suite speeds development by delivering pre-configured software that enables a range of popular features including rotary, slider and keypad functionality.

The complimentary software also helps lower system cost by eliminating the need for additional sensor silicon in many designs. Customers can choose a 3- or 12-pad Freescale sensor or the touch-sensing software solution for a variety of applications including:
— Home appliances: cooktops, ovens, refrigerators, washing machines
—Consumer and portable electronics: media players, audio/video systems, TV sets, PCs, monitors, notebooks, MP3 players, cameras
—Medical and industrial equipment: control panels, portable medical devices
—Remote and lighting controls
—Low-resolution touch screens for photo frames and GPS systems
—Large and small appliance touch panel interfaces
—Mobile phones and wireless connected device touch panels
—General use button replacements for netbooks and smartbooks
The chip supports up to 12 touch electrodes, plus a proximity function, it operates from 1.71 to 3.6V. All 12 electrodes are monitored at a 16ms (62.5Hz) sampling rate.

It allows continuous independent auto-calibration for each electrode, separate touch and release trip thresholds for each electrode and provides hysteresis and electrode independence.

The 3x3x0.6mm 20-lead QFN package drives up to eight LEDs or provides up to eight logic I/Os in any combination, in a -40 to +85 degree C temperature range.

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