Unbalanced Currents in Integrated Circuits and their Effect on TEM Cell Emissions

Abstract

Transverse ElectroMagnetic (TEM) cell measurements are often used to evaluate the potential of ICs to cause radiated emissions in printed circuit boards. These measurements are a function of the unbalanced current on package power pins, for example, where more current enters one side of an IC than another, and the displacement current caused by capacitive coupling from the power grid mesh to the septum of the TEM cell. The relationship between unbalanced currents and TEM cell measurements is derived in this paper. A distributed model of the on-die power delivery network is developed to show that unbalanced currents may be caused by an asymmetric power pin arrangement, by an imbalance in package impedance, or by an imbalance in the impedance of the on-die power delivery network. To validate results, the magnitude and phase of high-frequency power-pin currents were measured on a test chip. Experiments showed that results could be used to guide modifications to the chips connection to the printed circuit board power structure to minimize unbalanced currents and, thus, to minimize TEM cell measurements.

Department(s)

Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

Chip Scale Packages; Electric Power Transmission; Electromagnetic Compatibility; Electromagnetic Pulse; Integrated Circuits; Packaging; Printed Circuit Boards; Signal Interference; Timing Circuits; Displacement Currents; Distributed Modeling; Inductive Interference; Interconnect Power; Power Delivery Network; TEM-Cell Measurements; Transverse Electromagnetic Cell; Transverse Electromagnetic Cell (TEM); Electric Power Transmission Networks; Electromagnetic Inductive Interference; Electromagnetic Interference (EMI); Interconnect Power Systems; Transverse Electromagnetic Cell Emissions

International Standard Serial Number (ISSN)

0018-9375; 1558-187X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2011 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Aug 2011

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