Optimization and design of reference voltage for capacitive microaccelerometer

We develop the reference voltage for readout circuit of the capacitive microaccelerometer, and propose a novel optimization method for the reference voltage to ensure the stability of accelerometer. The optimal value of 1 V can be obtained by the optimization analysis. The reference circuit is implemented and verified using TSMC 0.35 μm CMOS process. Simulation results indicate that the circuit has a temperature coefficient of 7.54 ppm/°C from -25°C to 125°C. By analyzing the error sources of the proposed reference circuit, we find that the circuit inaccuracy is mainly caused by the offset-voltage of operational amplifier and the MOS mismatch, while the mismatch and tolerance of resistors have relatively smaller effect.