Design and realization of a universal capacitive readout integrated circuit

This paper introduces a gain-programmable low noise switched capacitor readout circuit for micro-electro-mechanical system (MEMS) accelerometer with signal bandwidth of 200 Hz. A two programmable capacitor arrays are also used to compensate the balanced capacitance offset that comes from the MEMS accelerometer. A brief equivalent model of the MEMS acceleration is introduced to simulate the transient response of the readout circuit. The proposed capacitor readout circuit has been fabricated in a three-metal two-poly 0.35 μm CMOS process. Measured results show that the readout circuit can sense difference and single capacitor with 78.1 dB dynamic.