A low temperature-dependence gain-boosting front-end amplifier for CMOS-MEMS gyroscopes

This paper describes a novel differential difference amplifier (DDA) with boosted gain, low temperature dependence, low noise and low power consumption for applications in monolithic CMOS-MEMS gyroscopes. The employed capacitive feedback achieves a 4fF equivalent transcapacitance with a 0.01%/°C temperature variation. The DDA-based interface circuits have been integrated with a z-axis gyroscope on a foundry CMOS chip. The DDA achieves a 24 dB gain and a 150 nV/VHz input-referred noise at 2 kHz, with a power consumption of 0.75 mW. The gyroscope is fabricated with a post-CMOS bulk micromachining process and it achieves a sensitivity of 0.3mV/°/s and a noise floor 0.27s/√Hz.