Smart CMOS capacitive pressure transducer with on-chip calibration capability

A capacitive pressure sensor with CMOS switched-capacitor circuitry for on-chip signal conditioning is introduced. It features differential generation and treatment of pressure-induced capacitance changes to suppress various parasitic effects. A digital calibration capability is provided for sensitivity adjustment and for temperature compensation. The fabrication of the transducer is largely congruent with a standard n-well CMOS process. The paper explains the function of the circuitry and its implications for the sensor design and presents experimental results obtained in testing the various components of the transducer as well the overall sensor system.