A fourth-order, audio-bandwidth, 87.5-dB SNDR ΣΔ modulator for MEMS microphones

Author

Picolli, L. ; Grassi, M. ; Rosson, L. ; Fornasari, A. ; Malcovati, P.

Author_Institution

Dept. of Electr. Eng., Univ. of Pavia, Pavia, Italy

fYear

2009

fDate

24-27 May 2009

Firstpage

1325

Lastpage

1328

Abstract

This paper presents a complete interface circuit for capacitive MEMS microphones, consisting of the cascade of a preamplifier, a second-order, multi-bit analog SigmaDelta modulator, and a fourth-order, single-bit digital SigmaDelta modulator. The complete interface circuit features a current consumption of 574 muA from a 3.3-V power supply, achieving a signal-to-noise and distortion ratio (SNDR) of 87.5 dB. The feed-forward technique has been used in the analog SigmaDelta modulator, to relax the requirements of the operational amplifiers. The proposed MEMS microphone interface circuit is designed in a 0.35-mum CMOS technology. Post-layout and Montecarlo simulation results of the overall circuit are reported to validate the performance.

Keywords

CMOS integrated circuits; Monte Carlo methods; micromechanical devices; microphones; operational amplifiers; sigma-delta modulation; CMOS technology; Montecarlo method; SNDR; capacitive MEMS microphone; cascaded preamplifier; current 574 muA; feed-forward technique; fourth order single-bit digital SigmaDelta modulator; operational amplifier; second-order multibit analog SigmaDelta modulator; size 0.35 mum; voltage 3.3 V; CMOS technology; Circuits; Digital modulation; Distortion; Feedforward systems; Micromechanical devices; Microphones; Operational amplifiers; Power supplies; Preamplifiers;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2009. ISCAS 2009. IEEE International Symposium on

Conference_Location

Taipei

Print_ISBN

978-1-4244-3827-3

Electronic_ISBN

978-1-4244-3828-0

Type

conf

DOI

10.1109/ISCAS.2009.5118008

Filename

5118008