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MC34063A: MC34063A getting damaged.

Vivek V
Prodigy 20 points
Part Number: MC34063A

HI Team

As discussed through live chat, in one of my ongoing projects, we are using MC34063A in our controller as a DC-DC buck convertor.

Over a period of time, Say 1 or 2 year. our customers are facing some failures in Controller, which upon doing root cause analysis, found that Power IC is getting burnt or damaged. attaching images and our Power IC circuit for your reference

Request your support to identify where this is going wrong.

  

thanks

Vivek

  • 0
    TI__Genius 17005 points

    Hello Vivek,

    Thanks for reaching out to us via e2e.

    Somehow I am not able to match the layout of your photo with the schematic.
    Anyway, it seems that the 3300µF capacitor is the only Input capacitor in your design.
    In addition, it is quite far away from the converter IC.
    For a Buck converter the input capacitor is very important.
    It needs to be fast, so it is essential that you are using ceramic capacitors (maybe some 10µF) which are close to the input pin of the converter IC.
    Also, the electrolytic capacitors need to be high quality Low ESR and low ESL types.
    The input look needs to be kept small. The VCC and GND pins need to have a short and solid connection to the ceramic input capacitor and also the distance to the electrolytic input capacitor should be as small as possible.

    I can only guess that - when the electrolytic capacitors are aging - there are too many over-and undershoots and the converter IS sees too much stress.

    Best regards
    Harry