Browse Prior Art Database

PLCC-44 (22+22) Heat Sink

IP.com Disclosure Number: IPCOM000101575D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Edwards, MJ: AUTHOR [+3]

Abstract

Disclosed is a snap-on, low-profile, very efficient heat sink for a PLCC-44 (22+22) package.

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PLCC-44 (22+22) Heat Sink

       Disclosed is a snap-on, low-profile, very efficient heat
sink for a PLCC-44 (22+22) package.

      A PLCC-44 (22+22) package is a Plastic Leaded Chip Carrier
(PLCC) of square shape with 11 pins on a side.  One set of opposing
rows of 11 pins (22 pins total) carry signals.  The other set of
opposing rows of 11 pins (22 pins total) are grounds.  The ground
pins are internally connected through a webbed copper lead-frame to
the chip substrate.  This connection provides a path for heat
dissipation through the 22 ground leads and onto the printed circuit
board (PCB) copper.  The heat sink concept described is applicable to
any package similar to the above which has heat-dissipating pins on
opposing sides of the package.

      The heat sink shown in the figure has interference-fit flanges
that snap over the opposing rows of ground pins of a pre-soldered
PLCC-44 (22+22).  This interference fit assures intimate contact
between the heat sink and the heat-conducting pins of the PLCC
package.  Holes may be provided for rivets, which would assure both
solid contact of the heat sink to the PCB copper for additional heat
conduction and maintenance of contact pressure between the heat sink
and the module pins.

      The heat sink provides conventional dissipation to the air
through the fins and external surfaces.  The part has a low-profile,
allowing use in stacked card and similar cramped situations.  The
orientation of the PC...