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  1. #1
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    How to get the operating temperature ( case temperature)

    Hi All,

    I have come across with this regulator and it just specifies the max thermal junction. I can just get temperature from the case, how could I calculate the max temperature possible on the case if I don't have the thermal resistance between junction and case?.

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    Re: How to get the operating temperature ( case temperature)

    Right there, on page 3, is Tjc, junction-to-case thermal resistance (only for the SOIC, however. Not sure why they left that parameter off for the other packages). There's also junction-to-ambient thermal resistance on the data sheet. If you're not using a heat sink, then that's all you need to know. Otherwise, you're going to have to contact the manufacturer.



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    Re: How to get the operating temperature ( case temperature)

    If you're of an experimental mood, you can use input
    or output ESD diodes, or possibly active pin attributes
    as a temperature proxy; a little oven time and some
    data points for diode Vf@If, and you've got yourself
    a regressable temp function. Need to stay away from
    imposed high power which could create gradients on
    the die and in the package, and respect any latchup pin
    current limits if you're testing the part "live".



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    Re: How to get the operating temperature ( case temperature)

    In still air, the center case top temperature of the package can be expected to be not much below the chip temperature, e.g. 10 - 20 K. We usually monitor it with a thermal imager.



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