ON THE PREDICTION OF DIGITAL CIRCUIT SUSCEPTIBILITY TO RADIATED EMI

The effects of radiated radio-frequency interference (RFI) on the oper ation of digital systems are studied by simulating the response of sim ple logic circuits to incident plane waves. The simulation is accompli shed by combining a linear electromagnetic moment-method model of the wire structure with a nonlinear circuit model of the solid-state compo nents, The complete model is analyzed in the linear and nonlinear regi mes as an example. It is shown how a circuit simulator, such as SPICE, can be used in the analysis of an arbitrary wire network loaded with logic circuits, by the process of representing the linear wire network as a lumped-element N-port pi network and interfacing it to the nonli near circuit simulator, Examples are given that demonstrate the occurr ence of both static and dynamic failures under various RFI-field excit ations and wire structure geometries. The prediction methods presented in this paper, can be used by emc engineers to assess the likelihood of failures in RFI-exposed digital systems.