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Dark current reduction by an adaptive CTIA photocircuit for room temperature SWIR sensing

  • Andrew Berkovich
  • , Alexander Castro
  • , Mohammad Islam
  • , Fow Sen Choa
  • , Geoffrey Barrows
  • , Pamela Abshire
  • University of Maryland, College Park
  • University of Maryland, Baltimore County
  • Centeye, Inc.

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Scopus citations

Abstract

We report an adaptive capacitive transimpedance amplifier circuit for room temperature sensing of short wave infrared (SWIR) radiation. The photocircuit reduces junction leakage current by measuring the current across a photodiode held at zero bias. This is critical to enable room temperature SWIR detection using materials with smaller bandgaps (and higher leakage current) such as InGaAs, which are typically operated at cooled temperatures. The transimpedance amplifier incorporates a floating gate current mirror in order to precisely cancel offset using nonvolatile analog storage. We experimentally verify that we are able to precisely tune the input offset and demonstrate a reduction in dark current of an InGaAs photodiode by two orders of magnitude, from 700pA to 2.25pA, when comparing similar adaptive and non-adaptive circuits. These circuits have been fabricated in a standard 0.6μm CMOS process.

Original languageEnglish
Title of host publicationIEEE International Symposium on Circuits and Systems
Subtitle of host publicationFrom Dreams to Innovation, ISCAS 2017 - Conference Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781467368520
DOIs
StatePublished - Sep 25 2017
Event50th IEEE International Symposium on Circuits and Systems, ISCAS 2017 - Baltimore, United States
Duration: May 28 2017May 31 2017

Publication series

NameProceedings - IEEE International Symposium on Circuits and Systems
ISSN (Print)0271-4310

Conference

Conference50th IEEE International Symposium on Circuits and Systems, ISCAS 2017
Country/TerritoryUnited States
CityBaltimore
Period05/28/1705/31/17

Keywords

  • active pixel sensor
  • CTIA
  • floating gate
  • image sensor
  • InGaAs
  • SWIR

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