Differential and common-mode transfer impedances are proposed herein to analyze noise coupled to (from) the dc power-bus from (to) via transitions in differential signals. Expressions for the two transfer impedances in terms of conventional single-ended transfer impedances are derived and verified through measurements, full-wave finite-difference time-domain (FDTD) simulations and an analytical cavity model. Some properties of the differential and common-mode transfer impedances are investigated to facilitate engineering design. The impact of signal current imbalances on power-bus noise and the benefit of differential signals as compared to single-ended signals are quantified.


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

Analytical Cavity Model; Common-Mode Transfer Impedances; Coupled Circuits; Coupling; DC Power Bus; Differential Signaling; Differential Signals; Electromagnetic Interference; Electronic Engineering Computing; Finite Difference Time-Domain Analysis; Full-Wave Finite-Difference Time-Domain Simulations; Microstrip Lines; Multilayer PCBs; Power-Bus Noise; Printed Circuits; Signal Current Imbalance; Signal Imbalance; Signal Integrity; Via Transition

International Standard Serial Number (ISSN)

1521-3323; 1557-9980

Document Type

Article - Journal

Document Version

Final Version

File Type





© 2005 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 May 2005