A power current model of LSIs for EMI simulation of digital printed circuit boards, and a parameter identification method based on the model are presented. The model consists of equivalent internal impedance and an equivalent internal current source. The equivalent internal impedance is obtained by measuring the impedance between the power and ground terminal of an LSI by means of an impedance analyzer, and an equivalent internal source is obtained from the measured current through the power terminal under the conditions of known external impedance. Furthermore, it is shown that simulation results generated using this model have good agreement with the results of measurements made under a range of external impedances.