A Low Noise Micro-gyroscope Interface Circuit on Chip with Demodulation Signal Phase Calibration Technique

A low noise interface circuit on chip is designed for capacitive micro-gyroscope with demodulation signal phase calibration technique. Fully differential trans-impedance amplifier structure is adopted in the readout circuits to optimize the noise performance, which achieves an equivalent input capacitive noise of 0.63 aF/\sqrt{Hz}. Dual channel quadrature demodulation technique and demodulation signal phase calibration technique are simultaneously applied to the sense channel, so that the interference of the mechanical quadrature signal is removed completely. The chip is implemented in 0.35m CMOS process. Experiments on a capacitive gyroscope show that an equivalent input noise of 0.01/s/\sqrt{Hz} is achieved. Under conditions of 8.5 mV//s scale factor and 5 V supply voltage, the full scale range of the gyroscope reaches 200/swith only 2 nonlinearity.