EMI Susceptibility Model of Signal Conditioning Circuits Based on Operational Amplifiers |
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Authors: | Gago J Balcells J Gonzalez D Lamich M Mon J Santolaria A |
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Affiliation: | Univ. Politecnica de Catalunya, Barcelona; |
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Abstract: | Circuits based on operational amplifiers (OPAMPs) are susceptible to electromagnetic interference (EMI) in the radio-frequency range due to the AM demodulation produced by non-linearity of internal transistors. Such a phenomenon produces demodulated signals in the low-frequency range. This paper presents a model to predict the susceptibility of analog signal-conditioning circuits, based on a few test parameters, while ignoring the internal structure of OPAMPs involved in the circuit. The method has been experimentally tested in two applications: (1) test of simple instrumentation adapter circuits and (2) predictions of susceptibility of an amplifier for an electret microphone, tested according to EN55020. |
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