Abstract: This article presents a highly digital Universal Sensors and Transducers Interface (USTI-MOB) with low power consumption, working in the capacitance measurement mode. The state-of-the art review of capacitance-to- frequency (time parameters) converters and commercially available capacitance-to- digital converters is provided. The proposed ASIP has the input capacitance range from 50 pF to 0.1 mF and average relative error < ±0.3 %. The USTI-MOB has 1.5 mW power consumption at +1.8 V supply voltage, and use a 4 MHz quartz oscillator. The IC has three popular serial interfaces: I2C, SPI and RS232/USB. Due to high metrological performances and technical characteristics the energy-efficient USTI-MOB is well suitable for such application as sensor systems for IoT, wearable and mobile devices. The ICs can also work with any quasi-digital capacitance converters, in which the capacitance is converted to frequency, period, time interval, duty-cycle or pulse width of square wave signals.

Keywords: Capacitance-to-digital converter, USTI-MOB, Capacitive sensors, Capacitance sensor interface, Capacitance-to-time converter, Capacitance-to-frequency converter.

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