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A Micro-Watt Second Order Filter for a Chopper Stabilized MEMS Pressure Sensor Interface

Authors: Minkyu Je, Wai Pan Chan, Arup K. George, Zhi Hui Kong

Abstract:

This paper describes a low-power second-order filter for a continuous-time chopper stabilized capacitive sensor interface, integrated with a fully differential post-CMOS surface-micromachined MEMS pressure sensor. The circuit uses a single-ended folded-cascode operational amplifier and two GM-C filters connected in cascade. The circuit is realized in a 0.18 μm CMOS process and offers differential to single-ended conversion. The novelty of the scheme is the cascade of two GM-C filters to achieve a second-order filter while minimizing power dissipation. The simulated filter cutoff frequency is 1.14 kHz at common-mode voltage 1.65 V, operating from a 3.3 V supply while dissipating 172μW of power. The filter achieves an operating range of 1V for an output load of 1MOhm and 10pF.

Keywords: MEMS, Pressure Sensors, chopper stabilization, Low pass filter

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1334944

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