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TAS56230 DKD package mounting

Hi. I'm just hoping for some pointers for attaching a PCB with a DKD package to a heatsink. SLMA004 mentioned in the TAS5630DKD data sheet doesn't have any relevant information regarding the package where the heat slug is on top. The top of the package has a tolerance of 0.5mm. If I'm going to be sure of good thermal contact in the worst case it means the PCB could be bent 0.5mm if the package is at the high side of the tolerance. The amount of pressure on the slug is determined largely by the thickness of the board and distance of the mounting points from the chip but I can't find any mounting guidelines at all.

tia

Gordon

  • Hi Gordon,

    A few guidelines can be found here.

    There was also a previous e2e discussion on the effects of different thermal compounds here 

    I would follow the heat sink layout used with our EVM as much as possible. The EVM users guide has some information on the heatsink used. I would talk with your PCB manufacturer on their flatness tolerances. If there processes or material causes a consistent bend/bow in the flatness of the PCB, make sure that the side with the amplifier pad is on the high side of the bend. Then when you attach the heat sink, the springiness of the PCB will help push the thermal pad into the heatsink.

    Best Regards,

    Matt Beardsworth

  • Thanks for the reply. The evaluation module uses the PHD package. Tolerance for the PHD as far as I can see is 0.2mm with a nominal package height of 1mm, quite different to the DKD package. "Secondly, be careful that you do not warp your board". That's going to be difficult with a tolerance of 0.5mm. Not to worry. I'm just going to have to make some sort of sprung loaded arrangement.

    Kind regards

    Gordon
  • Gordon,

    The caution there is to make sure the board does not warp pulling the device away from the heat sink. This would be very bad! If you can get a consisting slight warp in the other direction, then you can have a natural spring effect where the device power pad gets forced into the heatsink.

    Best Regards,
    Matt
  • I meant something like below which should provide adequate pressure without warping the board or relying on board flexibility.

    Regards

    Gordon