gEEk spEEk – PDN: Loss may be your Friend, but Inductance in your Enemy

Presented by: Istvan Novak For high-speed signaling, high-frequency loss is usually considered a bad side effect that we want to minimize. The DC loss, on the other hand, matters less, because in many high-speed signaling schemes we intentionally block the DC content. In power integrity it is almost the opposite: to deliver DC power, we want to minimize the DC losses, but at the same time we don’t want high-frequency noise to travel along the power distribution network. Therefore, AC losses in power distribution are usually helpful. Inductance is different though: while it is present in all conductive structures where current flows or could flow, in power integrity the only situation when we can consider it helpful, is when the inductance is in the series path as part of an intentional low pass filtering so that we can block the noise. In applications where we don’t need the power filtering, increased inductance comes with the downside that we need more capacitance to balance it.