On-Die Power-Rails Isolation Using Package Loop Inductance

This paper proposes package power distribution network (PDN) design methodology where multiple same voltage power rail bumps (PVDD and VDD) have isolation using package PDN loop inductance even after shorting those power bumps at package power layers of package stack-up. On-Die IO power rail isolation is provided for PVDD and VDD rails where isolation is physical i.e., there are separate PDN routes for PVDD and VDD. Higher package PDN loop inductance is typically seen as negative thing in power integrity but in the scenario considered in this paper, higher PDN loop inductance in package helps provide the necessary isolation between PVDD and VDD on-die power rails.