Digital programmable pressure sensor with on-chip CMOS signal processing and data storage

Monolithic sensors can greatly benefit from on-chip electronics since modern signal processsing has a potential to contribute significantly to improving overall sensor performance. This is important because semiconductor sensors usually exhibit crossensitivity and dependence on technology parameters, and also require biasing and signal amplification. This contribution presents a piezoresistive pressure sensor in which all relevant parameters (offset voltage, output signal, temperature coefficient of offset voltage, and sensitivity) are programmable in digital form on the chip. The sensor consists of a square diaphragm with four piezoresistors that form a wheatstone bridge and a programmable, analogue, on-chip readout as well as calibration electronics based on a 3fm n-well CMOS technology. The measuring range of the sensor developed amounts to 1.0 bar (10E5 Pa), the output signal is between 1.2 V (zero signal) and 4.75 V (F.S.O.) at a supply voltage of 8 V to 12 V.