Abstract: A simulation model is used to predict a semiconductor device's response to a single event upset. The simulation model is connected to a model of the semiconductor device to be tested. The simulation model switches in an impedance path between a node to be tested in the semiconductor device model and an opposite voltage supply until a predefined amount of charge has been reached via sourcing (for a low to high voltage transition) or sinking (for a high to low voltage transition). When the predefined amount of charge has been reached, the impedance path is switched out. The switching of the impedance path approximates the charge movement that occurs from a heavy ion strike passing through a sensitive volume. By varying the predefined amount of charge, the semiconductor device's susceptibility to SEU can be predicted without having to resort to physical testing.