CMOS integrated capacitive pressure transducer with on-chip electronics and digital calibration

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 in the form of a programmable capacitor array. The fabrication of the transducer is largely congruent with a standard n-well CMOS process. The paper explains the functioning of the circuitry and its implications for the sensor design and presents experimental results obtained in testing the various components of the transducer.