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Printed Circuit Board Power Bus Decoupling Questions

8. Can I use lossy capacitors or resistors to eliminate power bus resonances?

There is a good chance that the power bus resonances will already be damped in a densely populated board. They will also be highly damped in boards employing embedded capacitance if the plane spacing is about 0.01 mm or less. In boards that are not densely populated and don't employ embedded capacitance, it is usually possible to damp power bus resonances significantly using extra decoupling capacitors. These capacitors should be spread around the board and must have very low-inductance connections to the power planes.

Resonances between two power planes that at the same potential can be damped very effectively using resistors.


[1] T. Zeeff and T. Hubing, "Reducing Power Bus Impedance at Resonance with Lossy Components," IEEE Transactions on Advanced Packaging, vol. 25, no. 2, May 2002, pp. 307-310.