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LMZ31506: Temperature de-rating curve

Jessica Patterson
Prodigy 20 points
Part Number: LMZ31506

The temperature derating curve in the data sheet shows only a constant temperature. Is there a derating curve showing changing current with varying temperature at different output voltages? Most manufacturers have this graph, so I'm curious if it can be found for this product.

Thank you.

  • 0
    TI__Guru 50120 points

    Hi Jessica,

    There currently is no derating curve for changing current for this device. Is there a specific application you want to test for?

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    Prodigy 20 points

    Hi Jimmy,

    Thanks for replying. I'm looking to use this device at 5 V and would like to see how the current output changes with temperature, since I have seen that many power modules derate to as low as 3 V at high temperatures when running 5 V.

    Thanks,

    Jessica

  • 0 in reply to Jessica Patterson
    TI__Guru 50120 points

    Hi Jessica,

    The Figure 9 SOA graph in the datasheet implies that for all output voltage options, as long as the ambient temperature is at or below 85degC, the output voltage will be regulated and not droop for all load currents. I expect that at higher ambient temperature, the load current and input/output selection will result in the device's junction temperature to be above 125C and may result in slight lowering of output voltage regulation. I'm guessing you already looked at this.

    I can take an EVM, configure for 5Vin/3.3Vout, set the thermal chamber for two or three different temperature points (ie. 90C,95C,100C) and test regulation over full load current. However this will take some time depending on availability of the thermal chamber, so I can't get you an answer by today.

    Do you have a specific ambient temperature in mind? I can test for that specific use case of 5Vin/3.3Vout for the full current sweep to see if the output voltage every droops.

    Regards,

    Jimmy

  • 0 in reply to Jessica Patterson
    TI__Mastermind 19891 points

    Hello Jessica,

    The safe operating area curves (SOA), Fig 4, Fig 9, Fig 14, in the datasheet imply that there is no de-rating needed for the entire output current range. The maximum ambient in the application can be 85C. I think the y-axis should perhaps read "Maximum Ambient Temperature" instead of "Ambient Temperature". I believe this is where the confusion is coming from.

    Fig 15 shows the SOA for 5V out with 12V input. In that figure you can see a slight "knee" of de-rating at the max current.

    Let us know if this answers your question.

    Cheers,
    Denislav