A 97 dB dynamic range CSA-based readout circuit with analog temperature compensation for MEMS capacitive sensors

Abstract： This paper presents a charge-sensitive-amplifier （CSA） based readout circuit for capacitive microelectro-mechanical-system （MEMS） sensors. A continuous-time （CT） readout structure using the chopper technique is adopted to cancel the low frequency noise and improve the resolution of the rea...

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Published inJournal of semiconductors Vol. 34; no. 11; pp. 124 - 131
Main Author 尹韬 张翀 吴焕铭 吴其松 杨海钢
Format Journal Article
LanguageEnglish
Published 01.11.2013
Subjects
Choppers
Circuits
CSA
Drift
Dynamic range
MEMS
Noise levels
Semiconductors
Sensors
Temperature compensation
动态范围
模拟温度
温度补偿
电容传感器
读出电路
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ISSN1674-4926
DOI10.1088/1674-4926/34/11/115005

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Summary:Abstract： This paper presents a charge-sensitive-amplifier （CSA） based readout circuit for capacitive microelectro-mechanical-system （MEMS） sensors. A continuous-time （CT） readout structure using the chopper technique is adopted to cancel the low frequency noise and improve the resolution of the readout circuits. An operational trans-conductance amplifier （OTA） structure with an auxiliary common-mode-feedback-OTA is proposed in the fully differential CSA to suppress the chopper modulation induced disturbance at the OTA input terminal. An analog temperature compensation method is proposed, which adjusts the chopper signal amplitude with temperature variation to compensate the temperature drift of the CSA readout sensitivity. The chip is designed and implemented in a 0.35μm CMOS process and is 2.1 × 2.1 mm2 in area. The measurement shows that the readout circuit achieves 0.9 aF/√H capacitive resolution, 97 dB dynamic range in 100 Hz signal bandwidth, and 0.8 mV/fF sensitivity with a temperature drift of 35 ppm/℃ after optimized compensation.
Bibliography:capacitive readout circuit; temperature compensation; charge sensitive amplifier （CSA）; MEMS sensor
Abstract： This paper presents a charge-sensitive-amplifier （CSA） based readout circuit for capacitive microelectro-mechanical-system （MEMS） sensors. A continuous-time （CT） readout structure using the chopper technique is adopted to cancel the low frequency noise and improve the resolution of the readout circuits. An operational trans-conductance amplifier （OTA） structure with an auxiliary common-mode-feedback-OTA is proposed in the fully differential CSA to suppress the chopper modulation induced disturbance at the OTA input terminal. An analog temperature compensation method is proposed, which adjusts the chopper signal amplitude with temperature variation to compensate the temperature drift of the CSA readout sensitivity. The chip is designed and implemented in a 0.35μm CMOS process and is 2.1 × 2.1 mm2 in area. The measurement shows that the readout circuit achieves 0.9 aF/√H capacitive resolution, 97 dB dynamic range in 100 Hz signal bandwidth, and 0.8 mV/fF sensitivity with a temperature drift of 35 ppm/℃ after optimized compensation.
Yin Tao, Zhang Chong, Wu Huanming, Wu Qisong, Yang Haigang（Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China）
11-5781/TN
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1674-4926
DOI:10.1088/1674-4926/34/11/115005