The effects of quantizer metastability on the SNR of continuous-time /spl Sigma//spl Delta/ modulators with return-to-zero switched current DAC

Author

Le Guillou, Yann

Author_Institution

Philips Semicond., Caen

fYear

2006

fDate

21-24 May 2006

Abstract

This paper presents a study of the effects of the quantizer metastability in a continuous-time (CT) sigma-delta modulator (SigmaDeltaM). First, the implementation description of a CT SigmaDeltaM with a return-to-zero (RZ) switched-current (SI) DAC is presented. Then, starting with a theoretical description of the quantizer metastability, this non-ideality is analytically studied, modeled and its effect on the overall signal-to-noise ratio (SNR) is discussed. Some measurements on a real chip are done to validate the model accuracy. It is shown that the minimum gain-bandwidth (GBW) product of the practical integrated quantizer required to achieve the maximum SNR is predicted with less than 10% error

Keywords

comparators (circuits); digital-analogue conversion; network synthesis; sigma-delta modulation; switched current circuits; SNR; continuous-time modulator; integrated quantizer; minimum gain-bandwidth product; quantizer metastability; return-to-zero DAC; switched current DAC; Bandwidth; Circuits; Delta-sigma modulation; Latches; Master-slave; Metastasis; Sampling methods; Semiconductor device modeling; Switches; Threshold voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2006. ISCAS 2006. Proceedings. 2006 IEEE International Symposium on

Conference_Location

Island of Kos

Print_ISBN

0-7803-9389-9

Type

conf

DOI

10.1109/ISCAS.2006.1693007

Filename

1693007