[click to enlarge] Konfiguration for digital output [click to enlarge] Konfiguration for analog output [click to enlarge]

ZMD has expanded its family of capacitive sensor signal conditioning devices with the ZMD31210 cLite IC. It delivers 14-bit resolution and 0.5% accuracy. The ZMD31210 can be configured to interface with capacitive sensors from 2 to 260 pF with sensitivity as low as 125 atto-Farads (aF) per digital bit. The part accommodates both single and differential input sensor configurations. All calibration is digital, and completed in one pass; eliminating the cost of laser trimming and speeding production of fully-calibrated sensor modules.

The ZMD31210 connects to micro-controllers but can also be utilized in stand-alone designs for transducer and switch applications. The mixed signal design of cLite offers 14-bit capacitive-to-digital conversion and full 14-bit compensation of sensor offset, sensitivity and temperature via an internal digital signal processor running a correction algorithm. Calibration coefficients are stored in an on-board non-volatile EEPROM. The system interface offers I2C, SPI, PDM or alarm outputs.

The standard supply voltage is 2.7 to 5.5V. At this voltage, accuracy is 0.25% over the -20 to +85°C range, and 0.5% from -40 to +125°C. The ZMD31210 offers a 'Vcore' pin option for operation from 1.8V to 3.6V, with an accuracy of 1% from -20 to +85°C. Depending upon configuration, current consumption can be as low as 60μA. The Sleep Mode feature reduces consumption to less than 1μA.

Programming and single-pass calibration of the capacitive sensor and the ZMD31210 is available through a standard PC environment using the ZMD31210KIT development tools. The package includes TSSOP14 samples, a development board, USB cable and calibration software. The ZMD31210 is targeted for production in Q4/2009. Samples and kits are available. The devices are available in TSSOP14 packages. Unit prices start at 2.09 EUR, or USD 2.93, in volumes of 1k devices or more.