•  
• EDN Europe MAGAZINE
•  
• Free SUBSCRIPTION
• Subscription Renewal
• View Media Kit

• EDN
• EDN Australia
• EDN Asia
• EDN China
• EDN Japan

14-bit capacitive-sensor conditioning IC supports a range of sensor types

ZMDI has expanded its family of capacitivesensor signal-conditioning devices with the widedynamic- range ZSSC3123 IC. The chip delivers 14-bit resolution and 0.25% accuracy over a range of sensor capacitances and temperatures. Target applications include low-power-batterydriven sensor applications for humidity, weight scales, load and compression sensing, and tension control. The device suits MEMS-based sensor elements, such as pressure sensors for hydraulic-control systems, humidity sensors, and liquid-level gauges. The ZSSC3123 connects to microcontrollers, but you can also use it in stand-alone designs for transducer and switch applications. The ZSSC3123 can be configured to interface with 0.5- to 260-pF capacitive sensors. At supply voltages of 2.3 to 5.5V, the device is accurate to 0.25% over the −20 to +85°C range and 0.5% accurate from −40 to +125°C. You can use the device in both single- and differentialinput sensor configurations. It features an operating current as low as 60 μA over 2.3 to 5.5V. A built-in sleep mode lowers the current consumption to less than 1 μA for temperatures as high as 85°C. The IC has sensitivity as low as 125 aF per digital bit. The part provides SPI and I2C interfaces as well as PDM or alarm outputs. It uses digital techniques to correct both first- and third-order nonlinearity errors. Third-order correction is especially useful in humidity and pressure applications. Programming and single-pass calibration of the capacitive sensor and the ZSSC3123 are accomplished through a standard PC environment using the TSSOP14 development board and calibration software. The ZSSC3123 is available in die form and in a 14-pin TSSOP with a suggested retail price of $3.82 (1000). It operates over a −40 to +125°C temperature range.

—by Paul Rako

ZMDI, www.zmdi.com