A TIA-based interface for MEMS capacitive gyroscope

This paper presents a CMOS readout and driving interface for micro-electro-mechanical systems (MEMS) capacitive gyroscope. A low-noise fully differential trans-impedance amplifier (TIA) scheme is used both in readout channel and driving loop for capacitive signal detection. A linear model of amplitude control loop and the design of an AGC-based analog drive loop for gyroscope are presented. The model allows the small signal analysis and behavior prediction of the driving loop. The interface circuits are designed and implemented in a 0.35µm 2P4M CMOS process. The simulation results show that the TIA readout circuit achieves a capacitive resolution of 0.73aF/√Hz and dynamic range of 93dB from a single 5V supply.