A TIA-based readout circuit with temperature compensation for MEMS capacitive gyroscope

摘要

This paper presents an integrated readout circuit based on trans-impedance amplifier (TIA) for MEMS capacitive gyroscope. The feedback resistors in TIA are realized in T-network pattern, which provides on-chip trans-impedance gains up to 22MΩ. A CMOS temperature-variable gain circuit is proposed to compensate the temperature induced sensitivity variance in MEMS and TIA. The demodulator, instrumental amplifier and low-pass filter for signal processing are also integrated on chip. In order to simulate the response of the circuit to the vibrating gyroscope, a gyroscope simulation model implemented in Verilog-A HDL is established, which can take the MEMS parameters influence into account. The circuits measure 0.8×1.7mm² in a standard 0.35µm CMOS process. The simulation results show that the TIA achieves a capacitive resolution of 0.42aF/−Hz at 2.5kHz with 75ppm/°C temperature coefficient from a single 5V supply.