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    LNK304 input voltage below the datasheet minimum value...damage?

    Hello
    We are using the LNK304 on our PCB to supply 12V at 80mA.
    Mains is 240VAC.
    We wish to keep the input capacitance to the LNK304 at two parallel pieces of 100nF, 1812, 630V, X7R. (ie 200nF) This is due to cost reasons. And this is especially because we need flexi-term caps and above the 100nf value, they get very expensive.
    The problem is that if the mains falls to 210vac, then the input voltage of the LNK304 falls down to 29V every 10ms, as the rectified mains rises and falls. This is below the datasheet minimum vin of 50V. However, the 12v output of the lnk304 does not drop out.
    Should we be worried that out input voltage drops below the 50V minimum level? Ie will it mean damage caused to the LNK304?
    The LNK304 certainly doesn’t overheat in this situation.

    LNK304 datasheet
    http://www.mouser.com/ds/2/328/lnk30...306-179954.pdf

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  2. #2
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    Re: LNK304 input voltage below the datasheet minimum value...damage?

    I can't see anything in the data sheet that suggests damage will occur but running it below specified input might have consequences on the regulated output.
    I assume you are using a schematic similar to the constant current examples in the data sheet as an LED power source, the worst case I can think of is flicker in the LEDs as it can no longer keep the current stable.

    I would suggest investigating what happens yourself by using a variac at the input and monitoring the output as you adjust it.

    Brian.
    PLEASE - no friends requests or private emails, I simply don't have time to reply to them all.
    It's better to share your questions and answers on Edaboard so we can all benefit from each others experiences.


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