Power current modeling of IC/LSI with load dependency for EMI simulation

In this paper, we described how we modeled EMI noise from the power-pin current of an LSI that has two ports: a power-ground port and a driver output port. We named this modeling the "Linear Equivalent Circuit and Current Source for I/O (LECCS-I/O)" model and with it measured power current and power-ground impedance for various combinations of loading capacitances and decoupling inductances using a small scale IC (74LVC04). Results showed that up to 500 MHz, the LECCS-I/O model could predict peak and valley frequencies of the power current where the error was within 2.5 MHz, and where the peak current error was less than 5 dB. The application range of the LECCS-I/O model is valid where the non-overlap duration of the dumping oscillation wave between cycles is longer than twice the time constant of the waveform.