A 0.2-mW CMOS ΣΔ modulator for speech coding with 80 dB dynamic range

Author

vanderZwan, E.J. ; Dijkmans, E. Carel

Author_Institution

Philips Res. Lab., Eindhoven, Netherlands

Volume

31

Issue

12

fYear

1996

fDate

12/1/1996 12:00:00 AM

Firstpage

1873

Lastpage

1880

Abstract

A CMOS ΣΔ modulator for speech coding with continuous-time loopfilter is presented. Compared to switched-capacitor implementations, the relaxed bandwidth requirements of the active elements of the loopfilter reduce the power consumption. Furthermore, the need for an antialiasing filter at the modulator input is eliminated. A fourth-order, 64× oversampling ΣΔ modulator for application in portable telephones was designed and shows 80 dB dynamic range over the 300-3400 Hz voice bandwidth. Its input is directly connected to the microphone (maximum 40 mV_RMS). Total harmonic distortion (THD) is below -70 dB at 95 μA current consumption from a 2.2 V supply voltage. The active die area of the modulator is 0.5 mm² in a standard 0.5-μm CMOS process

Keywords

CMOS integrated circuits; audio equipment; continuous time filters; harmonic distortion; modulators; sigma-delta modulation; speech coding; 0.2 mW; 0.5 micron; 2.2 V; 300 to 3400 Hz; 3100 Hz; 95 muA; CMOS ΣΔ modulator; THD; continuous-time loopfilter; dynamic range; fourth-order oversampling ΣΔ modulator; portable telephones; power consumption; sigma-delta modulator; speech coding; total harmonic distortion; Bandwidth; Dynamic range; Energy consumption; Microphones; Modulation coding; Power harmonic filters; Speech coding; Telephony; Total harmonic distortion; Voltage;

fLanguage

English

Journal_Title

Solid-State Circuits, IEEE Journal of

Publisher

ieee

ISSN

0018-9200

Type

jour

DOI

10.1109/4.545807

Filename

545807