A fully integrated circuit for MEMS vibrating gyroscope using standard 0.25um CMOS process

Abstract

This paper presents an all-in-one fully integrated circuit solution for a vibrating micro-electromechanical gyroscope system using standard 0.25um 1P5M low voltage CMOS process. The analog parts of the system include a trans-impedance amplifier (TIA) with adaptive gain control (AGC) for the resonator driving loop, a sigma-delta modulator with gain/offset trimming function for the Coriolis signal read-out and a modified all PMOS charge pump for the high DC voltage. The digital signal processing parts include a trimming/control logic circuit and an I2C interface. SOG-bulk micromachining and deep reactive ion etching (DRIE) are adopted to fabricate the gyroscope sensor element with high aspect-ratio sensing structure and high yield. The experimental results indicate that the noise floor achieves 0.051° / s/ √Hz and the scale factor is 7mV/ °/s of the proposed two chip MEMS gyroscope system.