Home > ST Microelectronics’ new FingerTip touchscreen technology stifles electrical ‘noise’

ST Microelectronics’ new FingerTip touchscreen technology stifles electrical ‘noise’

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ST Microelectronics has announced the release of its new FingerTip capacitive sensing technology, which enables a single-chip solution for capacitive touchscreens up to 10" in diameter with multi-touch capability.

ST Microelectronics MEMS sensors and FingerTip capacitive sensing technology feature a sensing element connected to a high-performance capacitance-sensing circuit. The company has leveraged its knowledge in analog and mixed-signal interface technology to develop an innovative analog front end that is able to detect variations of capacitance in atto-Farads (10-18 F) and to immunise the system against noise.

Touchscreen applications are subject to noise coming from various sources, including the display, system, human touch, or battery chargers. Low cost and poor quality chargers, in particular, are a source of noise that can be as high as tens of volts and can affect normal operations when a finger touches the screen. In these instances, a strong periodic noise (in the frequency range from 1kHz to 1MHz) enters into the touchscreen controller’s analog front end and result in ‘false’ finger touches.

This new FingerTip capacitive sensing technology, with its powerful 32-bit DSP (digital signal processing) engine, is able to eliminate this charger noise effect and reach higher immunity levels without reducing performance in terms of accuracy, frame rate and power consumption.

FingerTip capacitive sensing technology has also been designed to eliminate noises from displays and works with both ‘in-cell’ and ‘on-cell’ display technologies.

“Noise from battery chargers pose a special issue for touchscreens, resulting in a poor user experience,” says Benedetto Vigna, General Manager of MEMS, Sensors and High Performance Analog Division.

“Our leadership in analog capacitive interface IP, developed for MEMS sensors, will allow us to achieve higher noise rejection prior to digital filtering. This new FingerTip capacitive sensing technology is able to achieve faster response time, low-power consumption and higher noise rejection required for high-end portable applications,” says Vigna.

Key benefits of FingerTip capacitve sensing technology include:

  • small stylus
  • very fast response time
  • ultra-low power consumption
  • best linearity and accuracy in noisy conditions; and
  • tiny package suitable for smart phones and 10" tablets.

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