Heat Spreader Implementation

[matthewware]

The Datasheet for MPC8640D says that "In any implementation of a heat sink solution, the force on the die should not exceed to pounds force".

1. If say an additional 10% of force, or a total of 11lbs force, would the die be at a high risk of damage?

2. Is that limit a constant clamping force, or a one lime installation force limit?

3. What would the main failure mode be if excessive force was applied? (fail at High current, immediate failure, failure at temperature. etc.)

Thanks!

[alexander_yakov]

MPC8640D package has exposed silicon die (lidless). The main threats are cracking of the die because of package bending or non-parallel alignment of heat sink.

Under no circumstances shall the total load exceed 80 N. Maximum short-term dynamic tensile force should not exceed 15 N (1.5 Kg equivalent). Maximum short-term dynamic compressive force shall not exceed 70 N (7.1 Kg equivalent).
Long-term static tensile forces are not allowed. Maximum long-term static compressive force on the package shall not exceed 45 N.

Reference document:
http://cache.nxp.com/files/32bit/doc/app_note/AN4871.pdf

Note. Aplication note allows more force to be applied for this package. We provide conservative requirments in datasheet.

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[DanielDuJijun]

Dear NXP Support Team.

Please help to share the download link for the following application note.

we cannot download AN4871 from the following link.

http://cache.nxp.com/files/32bit/doc/app_note/AN4871.pdf