Browse Prior Art Database

Printed Circuit Card Island

IP.com Disclosure Number: IPCOM000104061D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 4 page(s) / 86K

Publishing Venue

IBM

Related People

Siverling, MM: AUTHOR [+2]

Abstract

The concepts employed for electromagnetic compatibility between elements on a printed circuit card and their environment are disclosed. An island in a printed circuit card where the circuit interconnect and/or power supply ground return planes are disconnected from the adjacent planes to achieve EMI isolation. This isolation may involve circuit functions, or it may involve connectors for I/O purposes.

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Printed

Circuit

Card

Island

      The concepts employed for electromagnetic compatibility between
elements on a printed circuit card and their environment are
disclosed.  An island in a printed circuit card where the circuit
interconnect and/or power supply ground return planes are
disconnected from the adjacent planes to achieve EMI isolation.  This
isolation may involve circuit functions, or it may involve connectors
for I/O purposes.

      Fig. 1 is a cross-section of a printed circuit card.  The
bottom metal plane is the "ground" plane, the middle metal plane is
the power or voltage plane, and the top metal plane is assigned to
general circuit interconnects.  The insulating material between the
copper planes of the printed circuit card are indicated by the dotted
areas.  There could be other numbers of planes without changing the
spirit of the concept.  In Fig. 1, the island is defined as the area
where the planes are discontinuous (note the discontinuity in the
copper planes at the end points of the defined islands).

      Fig. 4 is the view of an island from a point perpendicular to
the planes.  The discontinuity in one or more planes is indicated by
the dotted lines defining the island.  The inner dotted line
indicates the outer perimeter of the island's discontinuous planes.
The area between the outer dotted line and inner dotted line is the
area of discontinuity where the plane's metal is removed, thus
forming the island that is separated from the plane structure of the
rest of the printed circuit card.

      Figs. 1, 2, and 3 indicate islands with special attributes for
particular purposes.

      Fig. 1 shows an island for isolating the noise on the general
printed circuit's power.  As part of the isolated circuit, capacitors
or other power storage devices are used to supply instantaneous power
to the isl...