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Page 13 of 34
IRAUDAMP10 REV
1.1
Check the TIM’s compression deflection with constant rate of strain (example as Fig.12) base on
manufacturer’s datasheet. According to the stress requirement, find strain range for the TIM. Then,
calculate heat spreader groove depth as below:
Groove Depth=DirectFET’s TIM’s Thickness*strain
**DirectFET’s height should be measured from PCB to the top of DirectFET after reflow. The
average height of IRF6775 is 0.6mm.
Fig 12 compression deflection with constant rate of strain