Splitting Planes For Speed and Power:Designers are sometimes confused about the question of how to deal with multiple power planes on printed circuit boards, and how to deal with their separation. We often talk about the horizontal separation between planes as a “split” and there are some design rules that may apply when designing in the area of splits. But before we talk about how to deal with splits between planes, it is instructive to talk about why we have separate power planes in the first place – to accommodate separate power supplies. And one reason we might have separate power supplies is because we might have different voltages in our circuits. So the issue of separate voltages might be a reasonable place to start.