Browse Prior Art Database

Squarcle Power Plane Clearance Lands

IP.com Disclosure Number: IPCOM000049687D
Original Publication Date: 1982-Jul-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Kershaw, JJ: AUTHOR [+3]

Abstract

When plated through holes (PTHs) in multilayer printed circuit es structured pass through power planes (PPs), a "clearance land" is provided to electrically isolate the PTH from those planes at which no connection is desired. This area of missing copper is normally round and of a diameter that will guarantee sufficient dielectric spacing from PTH to power.

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Squarcle Power Plane Clearance Lands

When plated through holes (PTHs) in multilayer printed circuit es structured pass through power planes (PPs), a "clearance land" is provided to electrically isolate the PTH from those planes at which no connection is desired. This area of missing copper is normally round and of a diameter that will guarantee sufficient dielectric spacing from PTH to power.

As the PTHs on new technology are spaced closer together and current demands on the power planes increase, it becomes more difficult to maintain enough dielectric spacing to accommodate normal plane to plane and drilled-hole misregistration without limiting the current carrying capacity of the power planes.

The squarcle configuration allows PTHs to be misregistered in both the X and Y axis while maintaining acceptable dielectric spacing with minimal impact on the current-carrying capacity of the power plane. The design of the squarcle for power plane application allows:
1. Enough copper removal in the right areas to increase the

plated through hole to power plane clearances to reduce

shorting conditions, improve manufacturing yield, and reduce

cost, and
2. Enough copper presence with the correct geometry so as not

to interfere with the electrical characteristics required to

meet the electrical parameters of the application (minimal

impact on current carrying capacity of the power plane).

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