Design of a CMOS Readout Circuit for Wide-Temperature Range Capacitive MEMS Sensors

Yucai Wang and Vamsy Chodavarapu
McGill University


We present a capacitance readout interface circuit in bulk CMOS process which is functional at wide temperature range between -55ºC to 175ºC. The proposed circuit uses a sigma-delta technique to convert capacitance ratio into a digital output and is suitable to provide a high-accuracy digitized output for capacitive MEMS sensors. The circuit is implemented using IBM 0.13μm CMOS technology with 2.5V power supply. Simulation results show that the circuit has excellent stability over wide temperature range, as high as 0.1% accuracy between -55ºC to 175ºC.