Browse Prior Art Database

Adaptation of LGA Socket Heatsink Retention Hardware to CGA Devices

IP.com Disclosure Number: IPCOM000123929D
Original Publication Date: 1999-Jul-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 3 page(s) / 99K

Publishing Venue

IBM

Related People

Brezina, J: AUTHOR [+2]

Abstract

Disclosed is a means of retaining a heatsink onto a CGA (column grid array) device (or alternatively a BGA ball grid array device) using an adaptation of a heatsink retention hardware set designed for use with socketed LGA (land grid array) devices. In the adaptation, the retaining posts on the heatsink are modified in length to accommodate the larger module height of a CGA compared to its LGA counterpart, and the backside springplate is modified to provide a substantially reduced load onto the CGA device compared to its LGA counterpart.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Adaptation of LGA Socket Heatsink Retention Hardware to CGA Devices

   Disclosed is a means of retaining a heatsink onto a CGA
(column grid array) device (or alternatively a BGA ball grid array
device) using an adaptation of a heatsink retention hardware set
designed for use with socketed LGA (land grid array) devices.  In the
adaptation, the retaining posts on the heatsink are modified in
length to accommodate the larger module height of a CGA compared to
its LGA counterpart, and the backside springplate is modified to
provide a substantially reduced load onto the CGA device compared to
its LGA counterpart.  The advantages of using this modified heatsink
retention hardware set for CGA devices are many:
  o  The hardware set for LGA and CGA devices is almost
     identical, creating many common parts that reduce
     parts management complexity and improve the cost by
     increasing overall volumes.
  o  Card features and hole patterns are identical for
     either socketed LGA devices or soldered CGA devices.
  o  The common heatsink retention hardware set and common
     card footprints allow modules to be socketed for bring-up
     and debug, and converted to CGA for production.
  o  The heatsink assembly procedure is identical,
     regardless of socketed LGA or soldered CGA applications.
  o  The allowable heatsink mass can be extended in the CGA
     application compared to other methods of heatsink
     retention on CGA devices, because the backside stiffener
     retards card bending during installation and during shock
     and vibration events that may occur during shipping, and
     because the heatsink is strain relieved laterally by the
     card itself.

   The exploded assembly drawing consists of the following
parts from left to right:
  o  Spring Plate Assembly (spring plate & threaded insert for
     load actuation)
  o  Backside stiffener
  o  Insulator
  o  Card
  o  CGA module soldered to card
  o  Heatsink Assembly (heatsink, retention posts, ground
     spring, ground spring protection bracket)

   Installation o...