The ZMD31210 cLite is a CMOS integrated circuit for accurate capacitance-to-digital conversion and sensor-specific correction of capacitive sensor signals. Digital compensation of sensor offset, sensitivity, and temperature drift is accomplished via an internal digital signal processor running a correction algorithm with calibration coefficients stored in a non-volatile EEPROM.

The ZMD31210 is configurable for many capacitive sensors with capacitances ranging from 2pF to 260pF and a sensitivity of 125aF/LSB to 1pF/LSB depending on the resolution, speed, and range settings (using 3-bit reference and 3-bit offset capacitances). It is compatible with both single capacitive sensors (both terminals must be accessible) and differential capacitive sensors. Measured and corrected sensor values can be output as I²C™, SPI, PDM, or alarms.
The I²C interface can be used for a simple PC-controlled calibration procedure to program a set of calibration coefficients into an on-chip EEPROM. The calibrated ZMD31210 and a specific sensor are mated digitally: fast, precise, and without the cost overhead associated with trimming by external devices or laser.

For quick and easy evaluation of the ZMD31210 and support for calibrating prototypes, ZMD offers the ZMD31210 Development Kit, which includes the Development Board, TSSOP14 samples, software, and documentation. Order using part number ZMD31210KIT.

• Target input capacitance range: 2pF to 260pF
• Programmable sampling rates: 8 to 14 bit; as fast as 0.75ms
• Digital compensation of sensor: piece-wise 1st and 2nd order sensor compensation or up to 3rd order single-region sensor compensation
• Digital compensation of 1st and 2nd order temperature gain and offset drift
• Internal temperature compensation reference (no external components)
• Programmable capacitance span and offset
• Layout customized for die-die bonding with sensor for low-cost, high-density chip-on-board assembly
• Supply voltage: 2.3 to 5.5V
• Current consumption as low as 60µA
• Sleep mode current <1µA (25°C)
• Operating temperature -40 to 125°C
• I²C and SPI for easy interface to microcontroller
• Up to two alarms that can act as full push-pull or open-drain switches
• Die or TSSOP14 package available

• Minimize calibration costs: no laser trimming,
  one-pass calibration using a digital interface
• Wide capacitance range to support a broad portfolio
  of sensor elements
• Excellent for low-power battery applications

• Designed for conditioning of capacitive sensor elements
• Pressure or humidity sensor modules
• Capacitive load cell measurements
• Liquid level gauges
• Linear and angular position sensing
• Contact-less potentiometer
• Hydraulic system
• Proximity
• Rain detection