AN INVESTIGATION OF DELTA-I NOISE ON INTEGRATED-CIRCUITS

The delta-I noise is the phenomenon of the voltage induced between the power conductors (e.g., the ground and the V(cc) planes) when a circuit connected between them switches from one state to another. This noise can endanger the performance of other circuits on the same chip or the printed-circuit board. In the existing literature, the noise has been considered primarily for integrated circuits, and it has been attributed solely to inductive effects. In this paper we show that the physics of the noise is more complex, and that it is related to the wave propagating effects. The delta-I noise should be present not only on integrated circuits (chips), but also on multilayered boards, where this noise should be pronounced when the transients are of the order of 1 ns or less. The investigations of the delta-I noise are carried out on a simplified model of power planes, using a wire-antenna numerical simulation program. The model includes the wave propagation effects, as well as radiation, but it does not include the effects of the dielectric filling out the space between the planes. The results of the analysis clearly show that the inductive effects are important only for slower transients. However, for fast digital circuits the power planes actually form a resonator, which can have a high quality factor, and the delta-I noise can build up to very high-voltage levels.