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TPS65987D: Maximum PD capability without FET

Ambroise Suter
Expert 4110 points
Part Number: TPS65987D
Other Parts Discussed in Thread: TIDA-050012

Hello,

Is it realistically possible to run TPS65987D at 20V and 5A and deiliver 100W without a FET?

How much heat needs to be dissipated in this case?

Thank you and best regards,

Ambroise

  • 0
    TI__Mastermind 30000 points

    Hi Ambroise,

    Would you be able to share a little more on the background for this question? Mainly, why are you considering not using a FET in the power path?

    Also by FET, are you referring to the power path internal to the TPS65987D or an external power path that is controlled by the TPS65987D? 

  • 0 in reply to Adam Mc Gaffin
    TI__Expert 4110 points

    Hi Adam

    The power path is referred to the internal PPHV .

    Since it's 100W passing through, thermal dissipation is a concern.

    With Rds_on of 30mohm, and 5A, it will dissipate 4.5W of heat.

    Junction to ambient thermal resistance is 57.7C/W, that equals 260C in temperature delta. Meanwhile, thermal shutdown at junction is 165C.

    The above calculation is assuming heat conducts through air, and it may not be that bad if majority of the heat is through copper pads on PCB.

    If TI has data on 100W continuous PD, please share the results.

    Best regards,

    Ambroise

  • 0 in reply to Ambroise Suter
    TI__Mastermind 30000 points

    Hi Ambroise,

    Thank you for clarifying. I do not have specific data about this test condition, but the internal power path is rated at 5A which you can see in the datasheet. So we run through internal testing/validation to verify this spec

    Also, if this application is a source only, you can think of using the power duo functionality which is explained in this reference design TIDA-050012