Low-power operation of a precision CMOS temperature sensor based on substrate PNPs

AL Aita, KAA Makinwa

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientific


In this paper, a low-power version of a high-precision smart temperature sensor in 0.7¿m CMOS technology is presented. The sensor consists of two main blocks: the bipolar front-end and the ADC. The sensor's power dissipation was reduced by reducing the bias current of the substrate PNP transistors - the temperature-sensing element - to the minimum levels set by accuracy requirements. To keep the same current density, the PNPs were reduced in size, as were the ADC sampling capacitors CS, so the sensor's conversion time is maintained. Increased mismatch errors due to the use of lower bias currents and smaller devices are mitigated by Dynamic Element Matching and chopping techniques. For an accuracy requirement of ±0.1°C, a minimum PNP bias current of 250nA is found. Measurement results for Ibias = 250nA and CS = 1.25pF show a 3¿ inaccuracy below ±0.3°C after offset calibration, and below ±0.08°C with a two-point calibration, from -55°C to 125°C.
Original languageUndefined/Unknown
Title of host publicationProceedings IEEE Sensors 2007
Editors s.n.
Place of PublicationAtlanta, USA.
PublisherIEEE Society
Number of pages4
ISBN (Print)1-4244-1262-5
Publication statusPublished - 2007
EventIEEE Sensors 2007: 6th IEEE Conference on Sensors - Atlanta, GA, United States
Duration: 28 Oct 200731 Oct 2007

Publication series



ConferenceIEEE Sensors 2007
CountryUnited States
CityAtlanta, GA


  • Elektrotechniek
  • Techniek
  • conference contrib. refereed
  • Conf.proc. > 3 pag

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