Thermal Interface Material (Tim); Structural Considerations - Intel X3350 - Xeon 2.66 Ghz 12M L2 Cache 1333MHz FSB LGA775 Quad-Core Processor Design Manual

Thermal Solutions
The assembly process for the 1U reference heatsink begins with application of
Honeywell* PCM45F thermal interface material to improve conduction from the IHS.
Tape and roll format is recommended. Pad size is 35 x 35mm.
Next, the heatsink is positioned such that the heatsink fins are parallel to system
airflow. While lowering the heatsink onto the IHS, the four captive screws of the
heatsink are aligned to the four threaded nuts of the back plate.
Using a #2 Phillips driver, torque the four captive screws to 8 inch-pounds.
This assembly process is designed to produce a static load of 39 - 51 lbf, for 0.062" -
0.100" board thickness respectively. Honeywell PCM45F is expected to meet the
performance targets in
Compressive Load of 0 - 60 lbf allows for designs that vary from the 1U reference
heatsink. Example: A customer's unique heatsink with very little static load (as little as
0 lbf) is acceptable from a socket loading perspective as long as the T
is met.
Compliance to board keepout zones in
process.
7.3.1

Thermal Interface Material (TIM)

TIM should be verified to be within its recommended shelf life before use. Surfaces
should be free of foreign materials prior to application of TIM. Use isopropyl alcohol and
a lint-free cloth to remove old TIM before applying new TIM.
7.4

Structural Considerations

The mass of the 1U and ATCA reference heatsinks does not exceed 500 gm.
From Table
exceed 500 gm as long as the mathematical product does not exceed 200 lbf. Example:
A heatsink of 2lb mass (908 gm) x 50 g (acceleration) x 2.0 Dynamic Amplification
Factor = 200 lbf. The Total Static Compressive Load
considered in dynamic assessments.
The heatsink limit of 500 gm and use of back plate have eliminated the need for Direct
Chassis Attach retention (as used with previous Dual-Core Intel
5000 sequence). Direct contact between back plate and chassis pan will help minimize
board deflection during shock.
Placement of board-to-chassis mounting holes also impacts board deflection and
resultant socket solder ball stress. Customers need to assess shock for their designs as
their heatsink retention (back plate), heatsink mass and chassis mounting holes may
vary.
August 2010
Order Number: 323107-002US
Table 7-1 from 30 - 60 lbf. From
5-3, the Dynamic Compressive Load of 200 lbf max allows for designs that
Table
Appendix B is assumed for this assembly
(Table
® ®
Intel Xeon Processor C5500/C3500 Series and LGA1366 Socket
5-3, the Heatsink Static
specification
CASE
5-3) should also be
® ®
Xeon processor
Thermal/Mechanical Design Guide
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