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"Phantom" Redundant Via

IP.com Disclosure Number: IPCOM000051533D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Getten, JR: AUTHOR

Abstract

When an internal circuit line in a printed circuit board is found to be defective or requires an engineering change, it must be deleted from the active electronic components in the circuit.

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"Phantom" Redundant Via

When an internal circuit line in a printed circuit board is found to be defective or requires an engineering change, it must be deleted from the active electronic components in the circuit.

In complex printed circuit boards and cards, the circuit lines are often not visually detectable as they are often buried deep within the board and are masked by power planes, other circuit lines or components. Therefore, deletion of internal circuit lines is generally achieved by mechanically removing the barrel of the plated through holes in the circuit, which often contain component or connector leads, or by bringing the circuit to the surface at each pin of the circuit net with an additional or redundant plated through hole. This surface line segment can then be mechanically severed to achieve the desired deletion. Both of these techniques have proven to be rather costly.

The present "phantom" redundant via approach economically solves the circuit deletion problem by drilling through the buried printed circuit at a known site just before the line reaches the plated through hole. This special site must be located such that a hole can be drilled into the printed circuit board to completely sever the line which is desired to be deleted without nicking or severing any other printed circuit lines or plated through holes. This special known site can be achieved in the following two ways: (1) Design in a special pad, as shown, to which the printed circuit...