{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,8]],"date-time":"2025-11-08T17:57:05Z","timestamp":1762624625312,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2021,7,9]],"date-time":"2021-07-09T00:00:00Z","timestamp":1625788800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":": This research was supported by a grant to Bio-Mimetic Robot Research Center Funded by De-fense Acquisition Program Administration, and by Agency for Defense Development","award":["UD190018ID"],"award-info":[{"award-number":["UD190018ID"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Air flow measurements provide significant information required for understanding the characteristics of insect movement. This study proposes a four-channel low-noise readout integrated circuit (IC) in order to measure air flow (air velocity), which can be beneficial to insect biomimetic robot systems that have been studied recently. Instrumentation amplifiers (IAs) with low-noise characteristics in readout ICs are essential because the air flow of an insect\u2019s movement, which is electrically converted using a microelectromechanical systems (MEMS) sensor, generally produces a small signal. The fundamental architecture employed in the readout IC is a three op amp IA, and it accomplishes low-noise characteristics by chopping. Moreover, the readout IC has a four-channel input structure and implements an automatic offset calibration loop (AOCL) for input offset correction. The AOCL based on the binary search logic adjusts the output offset by controlling the input voltage bias generated by the R-2R digital-to-analog converter (DAC). The electrically converted air flow signal is amplified using a three op amp IA, which is passed through a low-pass filter (LPF) for ripple rejection that is generated by chopping, and converted to a digital code by a 12-bit successive approximation register (SAR) analog-to-digital converter (ADC). Furthermore, the readout IC contains a low-dropout (LDO) regulator that enables the supply voltage to drive digital circuits, and a serial peripheral interface (SPI) for digital communication. The readout IC is designed with a 0.18 \u03bcm CMOS process and the current consumption is 1.886 mA at 3.3 V supply voltage. The IC has an active area of 6.78 mm2 and input-referred noise (IRN) characteristics of 95.4 nV\/\u221aHz at 1 Hz.<\/jats:p>","DOI":"10.3390\/s21144694","type":"journal-article","created":{"date-parts":[[2021,7,9]],"date-time":"2021-07-09T04:14:57Z","timestamp":1625804097000},"page":"4694","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["A Four-Channel Low-Noise Readout IC for Air Flow Measurement Using Hot Wire Anemometer in 0.18 \u03bcm CMOS Technology"],"prefix":"10.3390","volume":"21","author":[{"given":"Kyeongsik","family":"Nam","sequence":"first","affiliation":[{"name":"Department of Electronics Engineering, Chungnam National University, Daejeon 34134, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8428-9435","authenticated-orcid":false,"given":"Hyungseup","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Electronics Engineering, Chungnam National University, Daejeon 34134, Korea"}]},{"given":"Yongsu","family":"Kwon","sequence":"additional","affiliation":[{"name":"Department of Electronics Engineering, Chungnam National University, Daejeon 34134, Korea"}]},{"given":"Gyuri","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of Electronics Engineering, Chungnam National University, Daejeon 34134, Korea"}]},{"given":"Taeyup","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Automation System Research Institute (ASRI), Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, Korea"}]},{"given":"Chulhong","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Automation System Research Institute (ASRI), Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8040-5803","authenticated-orcid":false,"given":"Dongil","family":"Cho","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Automation System Research Institute (ASRI), Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, Korea"}]},{"given":"Junghoon","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5348-3585","authenticated-orcid":false,"given":"Hyoungho","family":"Ko","sequence":"additional","affiliation":[{"name":"Department of Electronics Engineering, Chungnam National University, Daejeon 34134, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"566","DOI":"10.1109\/JETCAS.2018.2825604","article-title":"Design of a CMOS MEMS accelerometer used in IoT devices for seismic detection","volume":"8","author":"Chiang","year":"2018","journal-title":"IEEE J. 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