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It is becoming increasingly common to distribute system power directly through a printed wiring backplane instead of using cumbersome and expensive cabling and bus bar techniques. However, distributing power through a thin sheet of copper with numerous clearance holes could lead to problems in meeting the overall system noise budget if care is not taken in properly determining the necessary amount of copper, and the proper placement of power attachment pints and loads. This paper describes the concept of DC noise margin and budgeting, provides insights into voltage gradients in printed wiring backplanes, and discusses generic design rules and gradient prediction techniques used at AMP Packaging System (APS). Two case histories have been included to reinforce and quantify the concepts.