When a printed circuit board (PCB) includes a power plane that is near to signal traces or other power planes, there is a significant risk of energy transfer between parts of the system. Not only does this coupling lead to power switching noise being transferred into data signals, it also means that power supply systems may demonstrate additional resonances that are not seen in the individual components. This can affect the power integrity of the PCB and may reduce its speed or reliability. This white paper will explore some of the potential power integrity issues that can affect a PCB and explain how simulation can be used to help reduce these effects.