Unbalanced Currents in Integrated Circuits and their Effect on TEM Cell Emissions
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.
K. Hu et al., "Unbalanced Currents in Integrated Circuits and their Effect on TEM Cell Emissions," IEEE Transactions on Electromagnetic Compatibility, vol. 53, no. 3, pp. 600-610, Institute of Electrical and Electronics Engineers (IEEE), Aug 2011.
The definitive version is available at http://dx.doi.org/10.1109/TEMC.2011.2118214
Electrical and Computer Engineering
Keywords and Phrases
Electromagnetic Compatibility; Electromagnetic Inductive Interference; Electromagnetic Interference (EMI); Interconnect Power Systems; Packaging; Transverse Electromagnetic Cell Emissions
International Standard Serial Number (ISSN)
Article - Journal
© 2011 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.