A highly EMI-immune folded cascode OpAmp in 0.18 μm CMOS technology

Subrahmanyam Boyapati, Jean-Michel Redoute, Maryam Shojaei Baghini

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4 Citations (Scopus)


This paper describes a folded cascode CMOS instrumentation amplifier input stage, which has an increased immunity to electromagnetic interference (EMI). The proposed structure uses a source-buffered concept with a replica circuit to achieve a higher EMI immunity over a wide range of frequencies, from 10 MHz to 1 GHz. Circuit simulations illustrate how the proposed folded cascode amplifier reduces susceptibility to EMI even in the presence of large amplitude interferences. Simulation results show that the maximum EMI-induced output offset voltage for the proposed folded cascode amplifier is less than 8 mV over a wide range of frequencies (10 MHz to 1 GHz), when a 3.3 Vpp EMI signal is injected into the non-inverting input; when the amplifier is connected in a voltage-follower configuration. In contrast, the classic folded cascode amplifier generates a maximum input offset voltage of 700 mV at 1 GHz under the same operating conditions.

Original languageEnglish
Title of host publicationProceedings of the 2016 International Symposium on Electromagnetic Compatibility (EMC Europe 2016)
Subtitle of host publicationWroclaw, Poland, 5 – 9 September 2016
Place of PublicationPiscataway NJ
PublisherIEEE, Institute of Electrical and Electronics Engineers
Number of pages6
ISBN (Electronic)9781509014163
ISBN (Print)9781509014170
Publication statusPublished - 8 Nov 2016
EventInternational Symposium on Electromagnetic Compatibility (EMC Europe) 2016 - Wroclaw, Poland
Duration: 5 Sep 20169 Sep 2016


ConferenceInternational Symposium on Electromagnetic Compatibility (EMC Europe) 2016
Abbreviated titleEMC Europe 2016

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