Capacitive-Sensing MCUs Lengthen Battery Life For HMI Apps

Capacitive-Sensing MCUs Lengthen Battery Life For HMI Apps

Combining Silicon Labs’ ultra-low-power technology with accelerated capacitive sensing, the C8051F97x microcontroller (MCU) family will find homes in human-machine interfaces (HMIs) used in Internet-of-Things, home/building automation, consumer, and industrial applications. The MCUs specifically target battery-powered and capacitive-touch-sensing applications for handheld industrial devices, toys, gaming machines, and remote controls, as well as touch-panel switch replacements for white goods. Their 200-µA/MHz active current and 2-ms wakeup time (transitioning from sleep to active mode) minimize energy consumption. In sleep mode, current is 55 nA with brownout detector enabled, and 280 nA with a 16.4-kHz internal oscillator. The F97x’s capacitive-sensing technology with sub-microamp wake-on-touch average current, 16-bit resolution, and 100:1 dynamic range supports buttons, sliders, wheels, and capacitive proximity sensing with up to 43 channels and multiple scanning mode. Incorporation of the company’s high-resolution, SAR charge-timing capacitive-to-digital converter (CDC) technology, which offers 40-µs acquisition time, speeds capacitive touch-sensing without sacrificing sensitivity performance. Up to 43 capacitive sensing inputs, 32-kbyte flash memory, 8-kbyte RAM, seven DMA channels, and a 16-by-16 multiply-accumulate (MAC) unit all squeeze into QFN packaging measuring down to 4 by 4 mm. Also integrated are a 25-MHz pipelined 8051-compatible core, oscillator, and 10-bit analog-to-digital converter.


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