Power Plane Resonance Analysis in a PCB

We often think about electronics in terms of circuit diagrams and equivalent circuits, but this eventually breaks down and we must consider the high-frequency characteristics of real electronic systems. In real PCBs, the propagating characteristics of electrical signals will dominate system behavior, including for something as simple as DC power distribution. DC power, particularly as it is drawn into a board by integrated circuits, is not really DC, which creates strongly resonant excitation in a PCB.

If you look at an impedance plot for the PDN in your PCB, you will notice that the plot has some resonant behavior at high frequencies. These frequencies generally fall into the GHz range and higher, depending on the structure and size of your circuit board. When the power and ground planes overlap in a PCB, the structure they create will form a semi-open parallel plate waveguide that has some distinct resonances.

In Cadence Sigrity PowerSI, the Resonance Analysis solver computes and displays all the resonant modes between predefined frequency ranges. You can also specify the number of resonant modes directly.

Click here to learn more about Power Plane Resonance Analysis in a PCB.

Team SimTech

Cadence Design Systems