ZMD has expanded its family of capacitive sensor signal conditioning ICs with the wide-dynamic-range ZSSC3123 IC. The chip delivers 14bit resolution over a range of sensor capacitances and temperatures. The IC is suitable for MEMS-based sensor elements, such as pressure sensors for hydraulic control systems, humidity sensors, and liquid level gauges. The IC connects to microcontrollers but can also be utilised in stand-alone designs for transducer and switch applications. The IC features an operating current of 60µA. A built-in sleep mode lowers the current consumption to less than 1µA for temperatures up to 85°C. The IC can be configured to interface with capacitive sensors from 0.5 to 260pF, with sensitivity of 125aF per digital bit.
The IC part can be used in both single- and differential-input sensor configurations. All calibration is digital and completed in one pass, eliminating the cost of laser trimming, and speeds up calibration of sensor modules in production, according to the company. Programming and single-pass calibration of the capacitive sensor and the IC is accomplished through a standard PC environment using the IC kit and development tools. The kit includes a TSSOP14, development board, USB cable and calibration software. At the standard supply voltage of 2.3 to 5.5V, the IC is accurate to 0.25% over -20 to +85°C, and 0.5% from -40 to +125°C. The IC part provides I2C and SPI interfaces as well as PDM or alarm outputs.
