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Anantha P. Chandrakasan. Cho, Taeg Sang Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science 2008-02-27T22:42:25Z 2008-02-27T22:42:25Z 2007 2007 http://hdl.handle.net/1721.1/40519 191870549 Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007. Includes bibliographical references (p. 95-98). A carbon nanotube is considered as a candidate for a next-generation chemical sensor. CNT sensors are attractive as they allow room-temperature sensing of chemicals. From the system perspective, this signifies that the sensor system does not require any micro hotplates, which are one of the major sources of power dissipation in other types of sensor systems. Nevertheless, a poor control of the CNT resistance poses a constraint on the attainable energy efficiency of the sensor platform. An investigation on the CNT sensors shows that the dynamic range of the interface should be 17 bits, while the resolution at each base resistance should be 7 bits. The proposed CMOS interface extends upon the previously published work to optimize the energy performance through both the architecture and circuit level innovations. The 17-bit dynamic range is attained by distributing the requirement into a 10-bit Analog-to-Digital Converter (ADC) and a 8-bit Digital-to-Analog Converter (DAC). An extra 1-bit leaves room for any unaccounted subblock performance error. Several system-level all-digital calibration schemes are proposed to account for DAC nonlinearity, ADC offset voltage, and a large variation in CNT base resistance. Circuit level techniques are employed to decrease the leakage current in the sensitive frontend node, to decrease the energy consumption of the ADC, and to efficiently control the DAC. The interface circuit is fabricated in 0.18 /m CMOS technology, and can operate at 1.83 kS/s sampling rate at 32 pW worst case power. The resistance measurement error across the whole dynamic range is less than 1.34% after calibration. A functionality of the full chemical sensor system has been demonstrated to validate the concepts introduced in this thesis. by Taeg Sang Cho. S.M. 98 p. eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Electrical Engineering and Computer Science. An energy efficient CMOS interface to carbon nanotube sensor arrays energy efficient complementary metal oxide semiconductors interface to CNT sensor arrays Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="42e0fe22-2125-4bdd-8e7d-61eb48d05e7a"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>An energy efficient CMOS interface to carbon nanotube sensor arrays</Title> <Subtitle>energy efficient complementary metal oxide semiconductors interface to CNT sensor arrays</Subtitle> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2007</PublicationDate> <Authors> <Author> <DisplayName>Cho, Taeg Sang</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Electrical Engineering and Computer Science.</Keyword> <Abstract>A carbon nanotube is considered as a candidate for a next-generation chemical sensor. CNT sensors are attractive as they allow room-temperature sensing of chemicals. From the system perspective, this signifies that the sensor system does not require any micro hotplates, which are one of the major sources of power dissipation in other types of sensor systems. Nevertheless, a poor control of the CNT resistance poses a constraint on the attainable energy efficiency of the sensor platform. An investigation on the CNT sensors shows that the dynamic range of the interface should be 17 bits, while the resolution at each base resistance should be 7 bits. The proposed CMOS interface extends upon the previously published work to optimize the energy performance through both the architecture and circuit level innovations. The 17-bit dynamic range is attained by distributing the requirement into a 10-bit Analog-to-Digital Converter (ADC) and a 8-bit Digital-to-Analog Converter (DAC). An extra 1-bit leaves room for any unaccounted subblock performance error. Several system-level all-digital calibration schemes are proposed to account for DAC nonlinearity, ADC offset voltage, and a large variation in CNT base resistance. Circuit level techniques are employed to decrease the leakage current in the sensitive frontend node, to decrease the energy consumption of the ADC, and to efficiently control the DAC. The interface circuit is fabricated in 0.18 /m CMOS technology, and can operate at 1.83 kS/s sampling rate at 32 pW worst case power. The resistance measurement error across the whole dynamic range is less than 1.34% after calibration. A functionality of the full chemical sensor system has been demonstrated to validate the concepts introduced in this thesis.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>