Analysis of sigma-delta micro-mechanical accelerometer´s parameters

Based on conventional 2nd-order and 4th-order closed-loop sigma-delta accelerometer (ΣΔ accelerometer) system models, an investigation into parameters that influence accelerometer´s performance is presented, including lead compensation coefficient, mechanical resonant frequency and input signal. Moreover, effect of compensation coefficient under high Q is researched. The simulation results imply that an accelerometer system has an optimal compensation coefficient and its performance is inversely proportional to resonant frequency. And the system is conditionally stable under different input acceleration. By optimizing these parameters, a 4th-order sigma-delta accelerometer with 93dB SNDR can be achieved.