Comparative Study of Single Quantization Architecture And Dual Quantization Architecture Electromechanical Sigma-Delta Modulators For MEMS Accelerometer

Abstract

An electromechanical sigma-delta modulator (EMSDM) has been popular in high-precision MEMS inertial sensors, since it is a good choice to achieve high system performances and directly output digital signal. This paper presents a comparative study of a single loop electromechanical sigma-delta modulators with single quantization architecture (EMSDM-SQA) and electromechanical sigma-delta modulators with dual quantization architecture (EMSDM-DQA) for MEMS capacitive accelerometers. The results of analysis, simulations and testing confirm that when the ADC in EMSDM-DQA is properly chosen, the effect of the ADC quantization noise can be neglected. The noise floor of the EMSDM-DQA is 141 ng/√Hz, which is 41% lower than that of the EMSDM-DQA.