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LMK04832: Dimensional limit required for Thermal pad stack calculation

Thendral J
Prodigy 20 points

Part Number: LMK04832

Tool/software:

Hi,

In the datasheet, I could only find the maximum height (3.53 mm) for the part, LMK04832W/EM.

Kindly specify the lower dimension also to help us select the right thermal pad.

Also, kindly specify the recommended pressure that can be exerted on the part.

Thanks in advance.

Regards,

Elanthendral.J

Sr. Mechanical design engineer.

  • 0
    TI__Mastermind 32152 points

    Hello Elanthendral, 
    20N max pressure. 
    Note we do not characterize pressure/compressive forces.
    Here is package outline. 

    Heat sink thickness must be 3.53-1.45-0.3-0.2. 
    Best regards, 

    Vicente 

  • 0 in reply to vicente flores prado
    Prodigy 20 points

    Hi Vincent, Thanks for the reply.

    Could you please specify the lower dimension limit for the heatsink height?

  • 0 in reply to Thendral J
    TI__Genius 17180 points

    Hi Elanthendral, 

    From the package outline, the heatsink height is 1.5mm +/- 0.1mm. Let me know if you have any other questions. 

    Regards, 

    Connor 

  • 0 in reply to Connor Lewis
    Prodigy 20 points

    Hi Connor,

    Thanks for the reply.

    With reference to the Page No.6 in the below link, as the Junction-to-case (top) thermal resistance [RθJC(top)] is 6.7°C/W is less than the Junction-to-board thermal resistance [RθJB] 7.4°C/W, we have considered the Top side as the heat sink & considered the the 3.53 (Max ) dimension for stackup analysis. So, we require the lower dimension limit also to check for the gap at worst case condition and to ensure contact while using thermal interface gap fillers.

    LMK04832W-EM

  • 0 in reply to Thendral J
    TI__Genius 17180 points

    Hi Elanthendral, 

    I'm manually calculating the max possible height as (1.5 + 0.1) + (1.45 + 0.15) + 0.3 = 3.5mm. Since the max height is listed as 3.53mm, we can assume that the 0.3mm measurement has a tolerance of 0.03mm that isn't shown on the diagram. Similarly, that means that the minimum possible total height is (1.5 - 0.1) + (1.45 - 0.15) + (0.3 - 0.03) = 2.97mm. Let me know if this is what you're looking for. 

    Regards, 

    Connor