A low noise interface circuit design of micro-machined gyroscope

The analyses of MEMS gyroscope interface circuit on thermal noise, 1/f noise and phase noise are made in this paper. A closed-loop differential driving circuit and a low-noise differential detecting circuit based on the high frequency modulation are designed to limit the noise. The interface chip is implemented in a standard 0.5 μm CMOS process. The test results show that the resolution of sensitive capacity can reach to 6.47 × 10⁻²⁰ F at the bandwidth of 60 Hz. The measuring range is ± 200°/s and the nonlinearity is 310 ppm. The output noise density is ${5.8}^{\circ }/(h\cdot \sqrt{Hz})$. The angular random walk (allen-variance) is ${0.092}^{\circ }/\sqrt{h}$ and the bias instability is 2.63°/h. (paper)