Killing blue led's

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  1. - 31st January 2008, 01:21 #1
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    Steve_88
    Steve_88 is offline Junior Member
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    Question Killing blue led's

    I've had many surface mount blue led's pass away after a few weeks of use.

    I'm using the led as an activity light, flashing when my PIC16F876 starts up and flashing every few seconds to show it is alive.

    I'm driving the led from the I/O of the PIC with a 750 ohm current limiting resistor.

    I just re-read the data sheet for this part and noticed it talks about both ESD and moisture causing problems. The moisture may be the issue, as these are used outside and generally not well protected, though they are in enclosures.

    With the latest LED's death, I scoped the LED and found that when the PIC I/O switched logic high (5 vdc) that I had only about 3/4 of a volt entering the led.

    Thoughts?

    Thanks, I'll attach the data sheet
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