LONDON — ChipSensors Ltd. (Limerick, Ireland), a startup with a technology that allows the surface of an integrated circuit to be used to sense temperature, humidity, certain gases, and even pathogens, has introduced a family of digital humidity and temperature sensors at the Sensors Exposition in Chicago Illinois.

Because the sensing medium sits within the dielectric above a conventionally manufactured CMOS IC, the technology can be used to create highly-integrated industrial, scientific and medical sensors, with the IC implementing ADC, microcontroller and transmission functions to send collected data off-chip.

And because the devices in the family only consume microwatts of power, the sensors are being touted as suitable for energy-scavenging and long-life battery applications in wireless networks, goods monitoring and logistics.

ChipSensors' CS114 single-chip I2C digital sensor chip comes in a QFN package measuring 4-mm by 4-mm. The CS115 offers the same die in a 4-lead SIP package option, while the CS124 adds an auxiliary sensor input channel to the on-chip analog-to-digital converter.

The resolution of the ADC was not provided in datasheets but the company quotes an accuracy of measurement of +/- 2.0 percent relative humidity from 20 to 80 percent relative humidity and a +/- 0.5 degree C temperature accuracy over the range *40 to +125 degrees C.

The device operates from a 1.8 to 3.6 volt power supply with a peak current draw of 400 microamps and an average current draw of 1-microamp when taking 1 sample per minute. Samples are currently available in small quantities for evaluation, with wider sampling planned for Q3 2009, and production scheduled for Q4 2009, the company said.

"We're seeing excellent linearity and performance in initial beta trials," said Kevin Styles, vice president of marketing at ChipSensors, in a statement. "We are keen to engage with OEM customers to evaluate our sensors across a diverse range of applications, from industrial and instrumentation to automotive and medical."

ChipSensors patented use of porous Low-K dielectrics on the CMOS chip surface as humidity and gas sensors was described in EE Times in 2007.

Related links and articles:

University of Cambridge spawns sensor spin-off

Micronas develops integrated flexible gas sensor platform

Sensirion : Humidity sensor suits demanding measurements

Zero power wireless sensors