On the Robustness of CMOS-Chopped Operational Amplifiers to Conducted Electromagnetic Interferences

Andrea Lavarda, Luca Petruzzi, Nejc Radez, Bernd Deutschmann

Research output: Contribution to journalArticle

Abstract

This paper deals with the robustness of low power chopped CMOS operational amplifiers (OpAMPs) to electromagnetic interferences (EMI) conducted at the device input stage. The main differences between chopped amplifiers and standard offset uncompensated ones are analyzed in terms of EMI susceptibility, achieving three main results. First, a new model is developed to show how chopping influences the amplifier susceptibility in a broadband sense, demonstrating that chopped OpAMPs generate a lower amount of EMI-induced offset from the nonlinear distortion with respect to standard ones because of the topological differences between the respective input stages. Second, a model to predict the effects of EMI appearing at the multiples of the chopping frequency is derived, showing that chopped OpAMPs can experience dc shift peaks because of the linear distortion of the disturbances whose frequencies hit the even multiples of the chopping frequency. Finally, the simultaneous presence of the technological offset and the offset produced by the nonlinear and the linear distortion of EMI in chopped OpAMP is illustrated by means of dedicated EMI susceptibility measurements performed on several devices designed to validate the analysis.

Original languageEnglish
Pages (from-to)478-486
JournalIEEE Transactions on Electromagnetic Compatibility
Volume60
Issue number2
DOIs
Publication statusE-pub ahead of print - 2017

Keywords

  • Broadband communication
  • Chopped operational amplifier
  • Choppers (circuits)
  • Electromagnetic interference
  • electromagnetic interference (EMI)
  • immunity
  • Nonlinear distortion
  • offset
  • robustness
  • Standards
  • susceptibility
  • Transfer functions

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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