Fault Isolation and Failure Analysis of Power Distribution Networks in PCBs

Abstract This paper presents a novel approach in analyzing power distribution network (PDN) from a failure analysis perspective. PDNs, although technically should only have DC component, due to the nature of digital systems it powers and the way current is drawn in time and frequency domains, it is essential to look at AC component as well. AC component: impedance plays a huge role in PCB power rails and the different components (active and passive) that connect to it. Different components (i.e., voltage regulators (VR), bulk capacitors, ceramic capacitors, etc.) influence different frequency ranges. Fault isolation is the first step in ensuring the failure location is identified. A combination of near field spectrum analysis and two-port shunt impedance enables the failure analyst to isolate the component that is failing/degraded through this approach. The aim of this paper is to showcase the alternate approaches available for failure analysis of power rail/PDN failures along with their limitations.