1 Introduction

Especially for DC-DC converters, meeting a low PDN Impedance is important to reduce the voltage variations due to strict load transient requirements. An ideal PDN design enables a DC-DC converter to supply a stable voltage to a load and maintain it within narrow margins. When designing a PDN, it is important to validate that the output impedance (or input impedance) of a DC-DC converter is meeting its target impedance and achieve low impedance value in the milliohm range. A PDN impedance analysis shows an overlay of the passive component impedances constituting the power network over frequency.

This application report describes a measurement method to evaluate the PDNs of a DC-DC converter, the 2-port shunt-through measurement. This method allows PDN designers to measure down to milliohm impedances while supporting measurement at very high frequencies.