Modeling, simulations and design of mems electromechanical sigma-delta modulator

In this article we present part of the design methodology, modeling and efficient simulation of high performance micro-electromechanical ΣΔ modulator used for MEMS accelerometer. The method is based on converting continuous-time model of the MEMS sensor and eventual analog loop filter into discrete time equivalent using impulse invariant transformation. The methodology is valid for any “MEMS based cantilever” sensor operating in a closed loop, where mechanical transfer function does not provide adequate noise shaping to reach high accuracy and resolution. Using proposed methodology makes possible to efficiently design, predict the behavior and stability of the loop and perform efficient system level simulations.