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OpAmp burn out

  1. Oct 7, 2011 #1
    Hi gents. In a rig several times an OpAmp LM-324 burns and melts (and support too ! ). The circuit works perfectly for many hours and suddently ... I must precise that high voltage ( -6 kV) is not very far. My question : is ESD able not only to destroy OpAmp but also to make it melting ?
  2. jcsd
  3. Oct 7, 2011 #2

    jim hardy

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    ESD can render it unable to withstand its normal low voltage supply.

    What do you suppose happens when it becomes a dead short circuit across say a 5 volt 3 amp supply?
    I dont know what you have, but there's the principle.
  4. Oct 7, 2011 #3
    Don't know your exact circuit. But it is very common to have low voltage circuits burn around high voltage. We made it a standard practice to put transorbs to protect all the inputs and even the power input. We never have any problem since. We even tested to make sure the LV circuit survive in hv arc.
  5. Oct 7, 2011 #4


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    Staff: Mentor

    Just to add to the others' comments. The destructive phenomenon is called "latchup" or "SCR latchup". Here is a wiki article about it, with pointers out to other reading:


  6. Oct 8, 2011 #5
    Many thanks for your replies. I effectively used Transil diode on imput but not on power supply. I'll correct this.
    Last edited by a moderator: Oct 8, 2011
  7. Oct 9, 2011 #6
    Has someone a photo of a real device where we can see the voltage divider used as entry to regulation loop ?
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