Characterization of the RFI Rectification Behavior of Instrumentation Amplifiers

Abstract

In this paper, the rectification behavior of popular in-amps (instrumentation amplifiers) is measured in both common- and single-ended RF noise injection modes. It is recommended that AD8221 be used in common mode RF noise injection environment, and AD8220 and AD8429 be used in single-ended RF noise injection environment. The mechanism of RF noise rectification inside in-amps is also discussed. It is verified that rectification mainly happens at the non-inverting input of two op-amps in the first stage of an in-amp. The DC voltage difference between inverting input and non-inverting input of the in-amp is further amplified, which will cause a large DC offset at the output. It is shown that symmetry of the first stage in an instrumentation amplifier is very important. The asymmetry of the first stage will increase the DC offset at the output dramatically.

Meeting Name

2018 IEEE Symposium on Electromagnetic Compatibility, Signal Integrity and Power Integrity, EMC, SI and PI 2018 (2018: Jul. 30-Aug. 3, Long Beach, CA)

Department(s)

Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Comments

This paper is based upon work supported partially by the National Science Foundation under Grant No. IIP-1440110.

Keywords and Phrases

Busbars; Measurement; Operational amplifiers; Radio interference, Common mode; DC offsets; DC voltage; Instrumentation amplifier; Rectification behavior; RF noise; RFI rectification; Single-ended, Electromagnetic compatibility

International Standard Book Number (ISBN)

978-153866621-0

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Aug 2018

Link to Full Text

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