Single-chip A/D converter for digital microphones with on-chip preamplifier and time-domain noise isolation

A 1-bit sigma-delta modulator (ΣΔΜ) with an on-chip preamplifier for digital electret microphones has been implemented. A differential gm-opamp-RC preamplifier eliminates the traditional single-ended JFET interface and is integrated with an on-chip ΣΔΜ by removing all external components. The propos...

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Bibliographic Details
Published inElectronics letters Vol. 45; no. 3; p. 1
Main Authors Le, H B, Nam, J W, Ryu, S T, Lee, S G
Format Journal Article
LanguageEnglish
Published Stevenage John Wiley & Sons, Inc 29.01.2009
Subjects
CMOS
Digital
Distortion
Microphones
Modulators
Noise
Noise levels
Preamplifiers
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Summary:A 1-bit sigma-delta modulator (ΣΔΜ) with an on-chip preamplifier for digital electret microphones has been implemented. A differential gm-opamp-RC preamplifier eliminates the traditional single-ended JFET interface and is integrated with an on-chip ΣΔΜ by removing all external components. The proposed time-domain noise isolation technique preserves circuit performance under a single power supply condition. The prototype implemented in a 0.18 μm CMOS technology achieves a 78 dB dynamic range and 62 dB peak signal-to-noise + distortion ratio (both A-weighted) with a current consumption of 450 μΑ under a 1.8 V supply.
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ISSN:0013-5194
1350-911X