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Pressure level to provide good mechanical, thermal and electrical contact with PowerPAD

user4292685
Intellectual 935 points
Other Parts Discussed in Thread: TAS5614LA

Hi Engineers,

Could you tell me how many pressure (N/mm2) is to provide good mechanical, thermal and electrical contact with PowerPAD? and how many pressure is limit for TAS5614LA?

Regards,

  • 0
    Intellectual 935 points

    Pls. is it possible to press the center of DDV package (11mm length against 14mm package length) as below?

  • 0 in reply to user4292685
    TI__Genius 9175 points
    Hello,

    The maximum heatsink mounting force for the DDV package is 95N. This comes out to a maximum pressure of 1.1 N/mm2.
    The minimum recommended force is 20N.

    As long as the 1.1N/mm2 maximum pressure is observed, there should be no issue using a smaller heatsink relative to the package. However, for best thermal performance, the heatsink must be at least as large at the PowerPAD.

    Best Regards,
    Matt
  • 0 in reply to Matthew Beardsworth
    Intellectual 935 points

    Hi Matthew,

    Thank you for your reply. I understand 1 maximum pressure is 1.1N/mm2.

    Based on this value, how much gap between heatsink and DAMP is allowable?

    At TI EVM Heatsink for DDV package, the gap between heatsink and DAMP is 1.02mm center.

    This value looks like setting the center of DAMP thickness without pin height.

    However DAMP thickness has 0.1mm tolerance and pin height is 0.1mm center. On the other words, the maximum height for DAMP is 1.2mm with pin height.

    My question is that how much pressure you estimate to DAMP in this worst case (maximum height : 1.2mm vs gap : 1.02mm).

    Regards,

  • 0 in reply to user4292685
    TI__Genius 9175 points

    Hello,

    Yes you are correct. The heatsink allows for a 1mm gap where as the DDV is 1.2mm tall. With this height difference, we insure that the heatsink is always in contact with the DDV PowerPAD. Mounting pressure is controlled through the torque of heatsink mounting screws.

    The mounting pressure can be calculated based on the screw size and thread pitch for a given torque. This will need to be calculated based on the contact area for your heatsink and the screws you plan to use.

    Best Regards,

    Matt