In this paper, frequency dependencies of deltanoise caused by variations of the on-chip switching activity have been analyzed by simulations for a complex computer system board with multi-chip module, especially the impact of coincidences with resonances of the power distribution system. The switching frequency and the noise source waveform have been varied in case of a single delta- step. For repeated deltasteps the power noise dependencies on the repetition frequency, the duty cycle and the damping of the resonant loop have been analyzed.
Simulations using switching current sources for on-chip switching have been confirmed by simulations with switching resistors plus dc voltage source. Mid-frequency noise simulations using SPEED2000 and noise voltage measurements yield the same results within 6% for the first and second voltage droops and overshoots, if the real resistance of power/ground vias and module pins are included in the simulation.