The Design of a High-Accuracy Sigma-Delta Modulator with 2-2 Mash Structure

A 2-2 mash Sigma-Delta modulator is presented in this paper. This 2-2 mash Sigma-Delta modulator consists of two 2-order cascade topology. Special parameters in the novel transfer function is calculated, that enables the modulator to process the signal ranging from supply tail to ground without losing linear performance. The overall circuit is designed with 0.35um standard mixed signal technology. At 1.92MHz sampling rate and 64 oversampling ratio, the measured signal-to-noise ratio for the overall circuit is more than 110dB around 1kHz.