Modeling on electromagnetic susceptibility of operational amplifier OPA694

This paper deals with the susceptibility prediction of integrated circuits against the conducted interference coupled on their power supply pins. An integrated operational amplifier OPA694 is studied as a first case. The integrated circuit electromagnetic (ICEM) model is used to describe the inner power distribution network of OPA694 by theoretical study and experimental measurement. A curve fitting method is proposed to obtain the ICEM model parameters from different kinds of measurements without knowing the precise inner physical structure information of OPA694. Then the direct power injection (DPI) experimental test is conducted to measure the susceptibility of OPA694 to conducted sine-wave noise. And from the immunity measurement, a common simulation susceptibility criterion is obtained. Finally the whole simulation model of DPI setup including the ICEM model of OPA694 is established to predict its susceptibility and the model is perfectly verified in a 200MHz frequency range.