Improving the Electromagnetic Immunity of Operational Amplifiers

Bernd Deutschmann, Gunter Winkler
Graz University of Technology
Institute of Electronics
Inffeldgasse 12, 8010 Graz, Austria

 

Abstract

To create electronic sensor systems that can withstand high levels of electromagnetic interference, it's crucial to use operational amplifiers that are designed to be EMI hardened.

This presentation shows several investigation results of conducted electromagnetic immunity measurements of operational amplifiers. By comparing electromagnetic interference rejection ratio (EMIRR) measurements to direct power injection (DPI) measurements, it will be demonstrated that the EMIRR measurement, which uses continuous wave (CW) interference signals, is not always reliable for predicting immunity against discontinuous interferences like pulse modulated signals.

Additionally, based on design guidelines it will be shown how operational amplifiers systems can be designed to withstand electromagnetic interferences and to work properly in an electromagnetic environment.