11.1. PDN Design Goals and Supply Budget

Power supply noise has a significant impact on the performance of electronic systems in general, and on interface systems in particular. Supply noise generates timing variations inside the interface link, which cause jitter and reduce the timing margin of the interface system. If supply noise is large, it can also generate signal distortions, reducing the voltage margin of the interface system, and eventually causing functional failures in the system. The power distribution network must provide power supplies of sufficient quality to meet the functionality and performance targets of the electronic system.

Figure 11.1 shows the range of possible supply voltages at a system component, and a sample waveform. The supply voltage varies over time around an average voltage, which can be different from the nominal supply voltage due to component tolerances in the voltage regulator module, or voltage drops due to resistance in the supply path.