Behavioral modeling of switched capacitive interfacing circuitry using MATLAB/SIMULINK

The simulation of sigma-delta modulators using behavioral modeling has become the corner stone and is a part of the core of today´s mixed-signal design and analysis. In this paper, precise behavioral modeling of generic switched-capacitive interfacing circuit is presented. A novel method of designing a sigma delta modulator is developed and implemented using MATLAB/SIMULINK tool to obtain a high resolution, low noise readout circuitry due to its ease in construction of complex modules. The topology consists of second order sigma-delta modulator which includes a 1-bit quantizer. An oversampling ratio of 256 was selected to give the best SNDR and safe circuit non-idealities. The implementation includes both the open-loop and closed loop modes to make the model a reliable tool for the design of low-power, particularly for their embedded high speed sigma-delta modulators used in MEMS technology. Evaluation and validation results from simulations of 2^nd sigma-delta modulators demonstrate that the model is valid and accurate.