IC operates as capacitive sensor signal conditioner.June 9, 2009 -
ZMD31210 cLite(TM) delivers 14-bit resolution and can be configured to interface with capacitive sensors from 2-260 pF with sensitivity as low as 125 atto-Farads/digital bit. Standard supply is 2.7-5.5 V with accuracy of 0.25% over -20 to +85°C range, and 0.5% from -40 to +125°C. ZMD31210 connects to micro-controllers but can also be utilized in stand-alone designs for transducer and switch applications, and calibration coefficients are stored in an on-board non-volatile EEPROM.
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Original Press release
ZMD
Grenzstrasse 28
Dresden, ,
Germany
ZMD cLite(TM) Capacitive Sensor Signal-Conditioning IC Delivers 14-Bit Resolution at Low Power
The ZMD31210 combines a wider range of input capacitance, operating temperature and power supply voltage for power-sensitive industrial, consumer and medical applications.
DRESDEN, GERMANY, MAY 26, 2009 - ZMD AG, a global supplier of analog and mixed-signal solutions for automotive, industrial, and medical applications, has expanded its family of capacitive sensor signal conditioning devices with the wide-dynamic-range ZMD31210 cLite (TM) integrated circuit (IC). The new design technology delivers 14-bit resolution and 0.5 percent accuracy over a wide range of capacitances and temperatures. Capacitive sensors offer several benefits, including very low power operation, and the ZMD31210 supports this with a low 60 uA current draw over a supply voltage range as low as 1.8V or as high as 5.5V.
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.
Capacitive Sensors
Capacitive sensors are widely found in many MEMS sensing elements. Examples include pressure sensors for hydraulic control systems, humidity sensors and liquid level gauges. Capacitive sensors are often favored for their small size and lower power consumption over resistive bridge sensors.
Capacitive sensors do not touch or make direct contact with the system being sensed, which makes them a preferred option for industrial linear and angular position sensors and contactless potentiometers, where harsh or explosive environments make other sensor technologies impractical.
"In close cooperation with key customers, we developed a digital technique to correct not only first-order, but second-order nonlinearity errors difficult or impossible to correct with a pure analog signal path," stated Thilo von Selchow, CEO of ZMD. "Second-order correction is especially useful in humidity and pressure applications, but it can of course correct for sensor imperfections in almost any situation."
Product Specifications
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 percent over the -20 to +85-degree C range, and 0.5 percent from -40 to +125-degree C. The ZMD31210 offers a 'Vcore' pin option for operation from 1.8V to 3.6V, with an accuracy of 1 percent from -20 to +85-degree C. Depending upon configuration, current consumption can be as low as 60µA.
The sleep mode feature reduces consumption to less than 1ìA, making the device ideal for battery-based and other power-sensitive applications.
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.
The URL for the product feature sheet is http://zmd.biz/pdf/ZMD31210-FeatureSheet.pdf
About ZMD AG
Founded in 1961, ZMD AG is a leading supplier of on-time, innovative, robust, high precision, and cost-effective analog mixed-signal silicon solutions for energy efficiency in automotive, mobile medical appliances and industrial automation. ZMD specializes in design and marketing of high temperature, high voltage and ultra low power application-specific integrated circuits (ASICs) and application-specific standard products (ASSPs). Its advanced circuit-design expertise allows it to offer ICs with operating temperatures as high as +160°C, and voltages from 0.85 V to 40 V. Headquartered in Dresden, Germany, ZMD has 270 employees worldwide and serves customers from the company's offices in Dresden, Stuttgart, Germany; Milano, Italy; Paris, France; the U.S. Pocatello, ID, Melville, NY; Tokyo, Japan and Hsinchu City, Taiwan. ZMD has design centers in Dresden, Stuttgart, Germany; Varna, Bulgaria and Madison, Wisconsin.
Contacts:
Gabriele Taschler,
Marketing Communications Manager,
T: +49.351.8822.668,
gabriele.taschler@zmdi.com
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