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LM26480: Extra current from SW2

Antenna_Head
Genius 11955 points
Part Number: LM26480

We have a use case for LM26480 where SW1 will supply ~0.5A, but SW2 must now supply 1.8A due to a recent design change.

1.8A is more than the 1.5A recommended rating of the device, but the peak ripple current is still less than the current limit of the device.

Since SW1 is running at such low current, it seems we still have thermal margin even if SW2 is running at higher current.

Also, the ambient temperature is limited to about 70 deg C.

Are there any concerns operates SW2 at the slightly higher 1.8A?  

thanks!

-Steve

  • 0
    TI__Expert 3350 points

    Hi Steve,

    The buck converters for the LM26480 are rated for as follows 

    You would still want to ensure your inductors are properly rated as as to prevent inductor saturation.

    Best,
    Emily

  • 0 in reply to Emily Kong1
    TI__Genius 11955 points

    Thanks; I am aware of the datasheet parameters, but you did not answer my question: 

    Are there any concerns operating SW2 at a slightly higher current given that SW1 is only modestly loaded? 

    Obviously, we would make sure that the inductors are rated adequately.  

    thanks!

    -Steve

  • 0 in reply to Antenna_Head
    TI__Expert 3350 points

    Steve,

    Typically the max current ratings is more about FET capability than thermals. It's possible that SW1 being at light load would provide a greater thermal margin with running SW2 at higher current, but this isn't a spec we measure. Monitoring the peak ripple current to be < than max over a "long" period of time is the biggest concern. My other recommendation is testing with the LM26480 EVM, unless you have an existing prototype design you're working with. 

    Best,
    Emily