Signal IC features operating current as low as 60uA

Zentrum Mikroelektronik Dresden AG (ZMDI) has rolled the wide-dynamic-range ZSSC3123 IC as an extension of its family of capacitive sensor signal conditioning devices. The 14bit chip can be used in low-power battery driven sensor applications, weight scales, load and compression sensing and tension control, stated the company.

Capacitive sensors are often favored for their small size and lower power consumption. The ZSSC3123 complements these features and provides an optimal solution for system designs, noted ZMDI. The device is designed for MEMS-based sensor elements, such as pressure sensors for hydraulic control systems, humidity sensors and liquid level gauges.

"Responding to sensor system designer needs, we have developed a digital technique to correct both first-order and third-order nonlinearity errors that were difficult or impossible to correct with a pure analog signal path," noted Steve Ramdin, product manager at ZMDI. "Third-order correction is especially useful in humidity and pressure applications, but it can correct for sensor imperfections in almost any situation."

The ZSSC3123 connects to MCUs but can also be used in standalone designs for transducer and switch applications. It can be configured to interface with capacitive sensors from 0.5-260pF, with sensitivity as low as 125aF per digital bit. The 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. Programming and single-pass calibration of the capacitive sensor and the ZSSC3123 is done through a standard PC environment using the ZSSC3123 kit and development tools. The kit includes a TSSOP14, development board, USB cable and calibration software.

At the standard supply voltage of 2.3-5.5V, the chip features an operating current as low as 60uA. The device is accurate to 0.25 percent from -20°C to 85°C, and 0.5 percent from -40°C to 125°C. A built-in sleep mode lowers the current consumption to The ZSSC3123 part provides I2C and SPI interfaces as well as PDM or alarm outputs. The ZSSC3123 is available for $3.82 in volumes of 1k devices.