A High-Performance Digital Interface Circuit for a High-Q Micro-Electromechanical System Accelerometer

Micromachines. 2018;9(12):675 DOI 10.3390/mi9120675


Journal Homepage

Journal Title: Micromachines

ISSN: 2072-666X (Online)

Publisher: MDPI AG

LCC Subject Category: Technology: Mechanical engineering and machinery

Country of publisher: Switzerland

Language of fulltext: English

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Xiangyu Li (Faculty of Information Science and Technology, Ningbo University, Ningbo 315211, China)
Jianping Hu (Faculty of Information Science and Technology, Ningbo University, Ningbo 315211, China)
Xiaowei Liu (MEMS Center, Harbin Institute of Technology, Harbin 150001, China)


Blind peer review

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Time From Submission to Publication: 11 weeks


Abstract | Full Text

Micro-electromechanical system (MEMS) accelerometers are widely used in the inertial navigation and nanosatellites field. A high-performance digital interface circuit for a high-Q MEMS micro-accelerometer is presented in this work. The mechanical noise of the MEMS accelerometer is decreased by the application of a vacuum-packaged sensitive element. The quantization noise in the baseband of the interface circuit is greatly suppressed by a 4th-order loop shaping. The digital output is attained by the interface circuit based on a low-noise front-end charge-amplifier and a 4th-order Sigma-Delta (&#931;&#916;) modulator. The stability of high-order &#931;&#916; was studied by the root locus method. The gain of the integrators was reduced by using the proportional scaling technique. The low-noise front-end detection circuit was proposed with the correlated double sampling (CDS) technique to eliminate the 1/<i>f</i> noise and offset. The digital interface circuit was implemented by 0.35 &#956;m complementary metal-oxide-semiconductor (CMOS) technology. The high-performance digital accelerometer system was implemented by double chip integration and the active interface circuit area was about 3.3 mm &#215; 3.5 mm. The high-Q MEMS accelerometer system consumed 10 mW from a single 5 V supply at a sampling frequency of 250 kHz. The micro-accelerometer system could achieve a third harmonic distortion of &#8722;98 dB and an average noise floor in low-frequency range of less than &#8722;140 dBV; a resolution of 0.48 &#956;g/Hz<sup>1/2</sup> (@300 Hz); a bias stability of 18 &#956;g by the Allen variance program in MATLAB.