CMOS-MEMS gyroscope using integrated diode-rings as interface circuits

This paper presents an interface circuit for CMOS-MEMS gyroscope using integrated diode-rings. A brief introduction for the CMOS-MEMS integration technology [1] using high-ratio isolation trench will be introduced first. The integration system contains a Z-axis capacitive bulk silicon gyroscope and an interface circuits using diode-ring doing the first demodulation. A detailed analysis for the integrated diode-ring both theoretically and through simulation is given. The designed circuits including diode-rings and the compensation circuits for the mismatch of the gyroscope comb capacitances are implemented in 1.2-um 2P3M standard CMOS process. The integrated circuits were measured and the result indicated that the performance of the integrated interface circuits for gyroscope is greatly improved compared to that built by PCB.