Intelligent differential pressure transmitter with multiple sensor formed on a (110)-oriented circular silicon diaphragm

A multiple piezoresistive gauge sensor was developed for application to intelligent differential pressure transmitters. The sensor can measure differential pressure, static pressure, and temperature. Three piezoresistive gauges are positioned on a (110)-oriented circular monocrystalline silicon diaphragm. Proper dimensional design and optimal gauge positioning maximize the output and minimize crosstalk. Using data maps, three voltage outputs are combined by a microprocessor unit to yield a compensated sensor output. An experimental sensor was fabricated and the compensation scheme was proved useful. The sensor accuracy was within ±0.1% of the full scale in the pressure range of ±80 kPa. The zero and span shifts were less than 0.25% for the temperature range of -20-60°C, and zero shift was less than 0.1% for the static pressure change of 15 MPa