
45732 AMD 780E Databook 3.10
© 2009 Advanced Micro Devices, Inc.
5-10
Proprietary
Package Information
Figure 5-2 RS780E Ball Arrangement (Bottom View)
5.3.2
Pressure Specification
To avoid damages to the ASIC (die or solder ball joint cracks) caused by improper mechanical assembly of the cooling
device, follow the recommendations below:
•
It is recommended that the maximum load that is evenly applied across the contact area between the thermal
management device and the die does not exceed 6 lbf. Note that a total load of 4-6 lbf is adequate to secure the
thermal management device and achieve the lowest thermal contact resistance with a temperature drop across
the thermal interface material of no more than 3°C. Also, the surface flatness of the metal spreader should be
0.001 inch/1 inch.
•
Pre-test the assembly fixture with a strain gauge to make sure that the flexing of the final assembled board and
the pressure applying around the ASIC package will not exceed 600 micron strain under any circumstances.
•
Ensure that any distortion (bow or twist) of the board after SMT and cooling device assembly is within industry