LGA775 Socket Heatsink Loading
72
Thermal and Mechanical Design Guidelines
Simulation shows that the solder joint force (F
axial
) is proportional to the board
deflection measured along the socket diagonal. The matching of F
axial
required to
protect the LGA775 socket solder joint in temperature cycling is equivalent to
matching a target MB deflection.
Therefore, the heatsink preload for LGA775 socket solder joint protection against
fatigue failure can be more generally defined as the load required to create a target
board downward deflection throughout the life of the product
This board deflection metric provides guidance for mechanical designs that differ from
the reference design for ATX//µATX form factor.
A.3.1
Motherboard Deflection Metric Definition
Motherboard deflection is measured along either diagonal (refer to Figure
d = dmax – (d1 + d2)/2
d’ = dmax – (d’1 + d’2)/2
Configurations in which the deflection is measured are defined in the Table
To measure board deflection, follow industry standard procedures (such as IPC) for
board deflection measurement. Height gauges and possibly dial gauges may also be
used.
Table
7–1. Board Deflection Configuration Definitions
Configuration
Parameter
Pro Socket
load plate
Heatsink Parameter
Name
d_ref
yes
no
BOL deflection, no preload
d_BOL yes
yes BOL
deflection with preload
d_EOL yes
yes EOL
deflection
NOTES:
BOL: Beginning of Life
EOL: End of Life
Summary of Contents for BX80570E8200 - Core 2 Duo 2.66 GHz Processor
Page 10: ...10 Thermal and Mechanical Design Guidelines...
Page 26: ...Processor Thermal Mechanical Information 26 Thermal and Mechanical Design Guidelines...
Page 82: ...Heatsink Clip Load Metrology 82 Thermal and Mechanical Design Guidelines...
Page 84: ...Thermal Interface Management 84 Thermal and Mechanical Design Guidelines...
Page 110: ...Fan Performance for Reference Design 110 Thermal and Mechanical Design Guidelines...
