Mechanical Enabling for the Intel Pentium 4 Processor in the 478-Pin Package

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Total clip stiffness (lb/in)
Re
q
uired
p
reload
(
lb
)
 Increase in clip stiffness


 Allows reduction in
required preload
 Reference design
leverages this
relationship to minimize
required preload:
 Clip stiffness = 1100 lb/in
 Required preload
 ~ 55 lb minimum
 ~ 70 lb nominal
Design Effectiveness
Processor Package Pull-Out - 3
Assumptions:
MB local stiffness ~ 1300 lb/in
HS load, F
HS
~ 100 lbf
*Note: Linear analysis: Not fully representative. Requires
non-linear finite element analysis for accurate assessment.
P
req
= F
HS
k
MB
k
clip
+k
MB
Clip Stiffness (lb/in)