A low-power low-noise capacitive sensing amplifier for integrated CMOS-MEMS inertial sensors

Deyou Fang*, Huikai Xie

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

8 Citations (Scopus)

Abstract

This paper presents a low-noise CMOS capacitive sensing amplifier with power consumption as low as 1mW for monolithic CMOS-MEMS inertial sensors. Low-power operation is achieved by using an open-loop, two-stage amplifier topology with fully differential input/output and chopper stabilization. High chopping frequency (up to 2 MHz) and capacitance matching with optimal transistor sizing are used to maximize signal-to-noise ratio. Offsets due to the sensor and circuits are reduced by ac offset calibration and dc offset cancellation. A pseudo-resistor MOS-Bipolar device is used to establish a stable dc bias at the sensing electrodes with very low noise. All the electronics, except the capacitor for the low-pass filter following the demodulation, are integrated on the same chip with MEMS inertial sensors. A prototype accelerometer integrated with this circuit has been fabricated using the TSMC 0.35-μm CMOS process with 3.3-V power supply. Experimental results show that this interface circuit achieves a gain of 40 dB over the chopper frequency range of 50 kHz to 1 MHz, with an equivalent input offset of about l mV. The sensor offset is attenuated by the interface circuit by more than 26 dB.

Original languageEnglish
Title of host publicationProceedings of the IASTED International Conference on Circuits, Signals, and Systems
EditorsM.H. Rashid
Pages96-101
Number of pages6
Publication statusPublished - 2004
Externally publishedYes
EventProceedings of the IASTED International Conference on Circuits, Signals, and Systems - Clearwater Beach, FL, United States
Duration: 28 Nov 20041 Dec 2004

Publication series

NameProceedings of the IASTED International Conference on Circuits, Signals, and Systems

Conference

ConferenceProceedings of the IASTED International Conference on Circuits, Signals, and Systems
Country/TerritoryUnited States
CityClearwater Beach, FL
Period28/11/041/12/04

Keywords

  • Capacitive interface circuits
  • Chopper stabilization
  • Integrated accelerometer
  • Low power
  • MEMS
  • Preamplifier

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Cite this

Fang, D., & Xie, H. (2004). A low-power low-noise capacitive sensing amplifier for integrated CMOS-MEMS inertial sensors. In M. H. Rashid (Ed.), Proceedings of the IASTED International Conference on Circuits, Signals, and Systems (pp. 96-101). Article 449-106 (Proceedings of the IASTED International Conference on Circuits, Signals, and Systems).