Signal-processing electronics for a capacitive micro-sensor

An interface circuit in a 0.8- mu m CMOS process for the on-chip integration of a capacitive micro-sensor used as a microphone is presented. In order to circumvent 1/f noise contributions and to improve the signal/noise ratio, a synchronous modulation-demodulation technique has been applied. For the...

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Bibliographic Details
Published in:Analog integrated circuits and signal processing 2001-10, Vol.29 (1-2), p.105-113
Main Authors: Amendola, G, Lu, G-N, Babadjian, L
Format: Article
Language:English
Online Access:Get full text
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Summary:An interface circuit in a 0.8- mu m CMOS process for the on-chip integration of a capacitive micro-sensor used as a microphone is presented. In order to circumvent 1/f noise contributions and to improve the signal/noise ratio, a synchronous modulation-demodulation technique has been applied. For the implementation of this technique, we have studied and designed several functional block, such as modulator with signal conversion, low-noise amplifier, demodulator, etc. To deal with problems related to dispersions of intrinsic capacitance of the sensor, a feedback compensating solution is suggested. The designed circuit has a sensibility of 1200 V/pF, with a minimum detectable capacitance variation of 2 10 super(-6) pF.
ISSN:0925-1030
DOI:10.1023/A:1011238515922