Silicon Pressure Sensor Uses MEMS Technology

STMicroelectronics' LPS001WP is a tiny silicon pressure sensor that uses aninnovative technology to provide extremely high resolution measurements ofpressure - and altitude - in an ultra-compact and thin package that can be used insmart phones, sports watches and other portable equipment, as well as inweather stations and automotive and industrial applications.

TheLPS001WP has an operating pressure range of 300 - 1100 millibar, correspondingto the atmospheric pressures between -750 and +9000 m relative to sea level,and can detect pressure changes as small as 0.065 millibar, corresponding to80 cm of altitude. The device is fabricated using a proprietary STtechnology called "VENSENS" that allows the pressure sensor to be fabricated ona monolithic silicon chip. Manufacturing the device in this way eliminateswafer-to-wafer bonding and maximizes reliability.

Thepressure sensor in the LPS001WP is based on a flexible silicon membrane formedabove an air cavity with a controlled gap and defined pressure. The membrane isvery small compared to traditional silicon micro-machined membranes and isprotected from breakage by built-in mechanical stoppers. The membrane includesa piezoresistor, a tiny structure whose electrical resistance varies as themembrane flexes in response to changes in the external pressure. The change inresistance is monitored, thermally compensated, and converted to a digitalvalue that can be read by the equipment's host processor using theindustry-standard I2C or SPI communications protocols.

Main technical features ofthe LPS001WP