Analyzing power integrity issues from power plane interactions

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 – affecting the power integrity of the PCB and reducing speed and reliability. This white paper takes a look at reducing these effects through the use of electromagnetic simulation.

Miniaturization and economization mean that PCB manufacturers are producing boards with high packing densities and as few layers as possible. In addition, modern PCBs often require several supply voltages, and therefore must include multiple power planes. This leads to circuit boards that include pairs of power planes which are not separated by ground layers, and such power planes can easily couple to each other. These effects can arise whether the planes are on the same layer or on adjacent layers.

Each power plane will have certain resonances, and the coupling to other planes can change these resonant frequencies. Since the resonances affect the impedance of the power distribution network, it is very important for the designer to consider these resonances when laying out the board.

Another common cause of power integrity issues is the use of stack-ups with signal traces running between a ground plane and a power plane. These traces can couple to the power planes as well. Not only can this change the resonances of the power planes, it also means that noise can be transferred into the data traces.

Read and download the full whitepaper below.