cLite – A Capacitive Signal Conditioning IC

Abstract

The ZMD31210 cLite™ – a new member of the ZMDI’s Lite™ family of low-cost sensor signal conditioner (SSC) integrated circuits – is described in this paper. The cLite™ is the first conditioner for capacitive sensors. Supporting sensor capacitances from 2 pF up to 260 pF, the new sensor signal conditioner covers a wide range of applications. An important aspect of conditioning a capacitance sensor input signal is the adaptation of the capacitive-to-digital converter (CDC) input range to the sensor signal span and offset values in order to maximize accuracy. All typical features of the Lite™ family including the digital calibration math based on EEPROM-stored coefficients and a variety of outputs (I2C™, SPI, PDM, and programmable alarms) are integrated in the cLite™ as well. Additional features including a sleep mode and low supply voltage range (down to 2.3 V) support the low power concept. The paper focuses in particular on the capacitance sensor adaptation and high precision sensor conditioning.

Keywords

• Sensor signal conditioner
• End-of-line calibration
• Capacitive sensor conditioning