Detect VR noise coupling sources through near field scanning

Abstract

This paper uses near field scanning (NFS) techniques to detect noise coupling sources due to switching voltage-regulators (VR) in a typical computer system. The fast switching of the VR FETs couples significant amounts of noise to signal lines in proximity, resulting in degraded signal performance, system malfunction, etc. Detecting all the potential noise sources has been a challenging task due to the complexity of VR design and the layout of the board. The near field scanning technique is utilized as a brute-force measurement-based method to identify and verify potential noise sources. Applications of the techniques are reported in the paper, where noise sources are revealed and design changes are made to mitigate the noise coupling issue.