Analog Integrated Circuits and Signal Processing

, Volume 97, Issue 3, pp 405–415 | Cite as

Design of a fA wide dynamic range ADC for current sensing

  • Evgenia VoulgariEmail author
  • Matthew Noy
  • Francis Anghinolfi
  • François Krummenacher
  • Maher Kayal


Current sensing is important in various applications. The Utopia 2 Application Specific Integrated Circuit (ASIC) was developed in AMS 0.35 \(\upmu \hbox {m}\) technology for radiation monitoring based on ionization chambers. The ASIC is able to measure current equal to 1 femtoampere (fA) after active leakage current compensation. The compensation is achieved with a second dummy compensating channel that is matched to the measuring channel. The ASIC was also designed to cope with input currents that span over nine decades of dynamic range. The analog to digital conversion is performed with charge balancing and counting. The maximum current that is equal to 5 \(\upmu \hbox {A}\) can be measured after the introduction of a second range. The system has been characterized at a certified laboratory and is able to sense currents from 1 fA up to 5 \(\upmu \hbox {A}\).


Femtoampere digitizer Current-to-frequency conversion Current readout circuit Leakage current Femtoampere current measurements Current sensing 



The authors would like to thank the Occupational Health and Safety and Environmental Protection (HSE) Unit of CERN for the financial support in this project and for the fruitful discussions during the development of the system.


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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Electronics LaboratoryÉcole Polytechnique Fédérale de Lausanne, EPFLLausanneSwitzerland
  2. 2.EP-ESE-FEEuropean Organization for Nuclear Research, CERNGenevaSwitzerland

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