EBG-Based Grid-Type PDN on Interposer for SSN Mitigation in Mixed-Signal System-in-Package

A novel electromagnetic bandgap (EBG)-based grid-type power distribution network (PDN), or grid-type EBG (GT-EBG), is proposed for interposer PDN. The behavior of the proposed EBG structure at cutoff frequencies is first analyzed, and a simplified circuit model is proposed to help control the bandgap behavior. Then the proposed design is realized with the integrated passive device process and validated by measurement. The measured stopband ranges from 7.5 to 15 GHz with an isolation level of -40 dB and 70% fractional bandwidth. In general, the GT-EBG consisting of different numbers of power/ground lines could be embedded in grid-type PDN for different bandgaps.

I. Introduction

To achieve high bandwidth, good electrical performance and compact size for integrated-circuit systems, the advanced interposer technology could not only integrate different ICs and share the same feeding power but also offer very fine metal pitch to contain more I/O signals. As transient currents drawn by digital ICs from interposer flow through the parasitic inductance of PDN, simultaneously switching noise (SSN) is induced [1]. As shown in Fig. 1, SSN not only propagates along the interposer, degrading power integrity (PI) and signal integrity (SI) of other ICs, but also induces near-field coupling and radio frequency interference (RFI), lowering the throughput of RF modules in the vicinity. Fig. 1.

Propagation of SSN noise through conductive, coupling, and radiative paths on interposer of mixed-signal system-in-package.