On reducing leakage quantization noise of multistage ΣΔ modulator using nonlinear oscillation

Teng Hung Chang*, Lan-Rong Dung, Jwin Yen Guo

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations

Abstract

This paper presents an improved architecture of the multistage (MASH) multibit sigma-delta modulators (ΣΔMs). The architecture can be immune to circuit nonidealities over a large portion of input range when oversampling ratio (OSR) is low, and hence the dynamic range (DR) can be improved. Our approach is based on two resonator topologies, high-Q cascade-of-resonator-with-feedforward (HQCRFF) and low-Q cascade-of-integrator- with-feedforward (LQCIFF). The key to improving DR is to use HQCRFF-based single-bit structure in the first stage and have the first stage oscillated. When the first stage oscillates, the coarse quantization noise vanishes and hence circuit nonidealities, such as finite op-amp gain and capacitor mismatching, do not cause leakage quantization noise problem. In addition, because of the in-band zeros introduced by the resonators, the proposed architecture enhances the suppression of the in-band quantization noise for wideband applications. As the results of simulation, the proposed MASH architecture can inherently have wide DR without using additional calibration techniques.

Original languageEnglish
Article number1465147
Pages (from-to)2555-2558
Number of pages4
JournalProceedings - IEEE International Symposium on Circuits and Systems
DOIs
StatePublished - 1 Dec 2005
EventIEEE International Symposium on Circuits and Systems 2005, ISCAS 2005 - Kobe, Japan
Duration: 23 May 200526 May 2005

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