How to check if the LM2577T -ADJ P+ counterfeit or original

Discussion in 'General Electronics Chat' started by dante_clericuzzio, Aug 1, 2016.

  1. dante_clericuzzio

    Thread Starter Member

    Mar 28, 2016
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    asdfdsaf
     
    Last edited: Aug 1, 2016
  2. Papabravo

    Expert

    Feb 24, 2006
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    They are likely to be manufacturing lot numbers and/or date codes. External markings are not a reliable way to tell much of anything about an IC, except if you can rub the marking off. Burning them out can happen for a variety of reasons. It often happens when somebody builds their first SMPS. These circuits can be tricky and often do not perform well on breadboards; they require careful layout on a printed circuit board.
     
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Are you sure it is burned out - that chip also has a thermal protection, under-voltage lockout and current limiting to protect itself.

    • Output Switch Protected by Current Limit, Under-voltage Lockout, and Thermal Shutdown
     
  4. Papabravo

    Expert

    Feb 24, 2006
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    If the thermal protection has tripped then the chip is obviously being abused in some way. You might want to reconsider your circuit to understand why things are getting so hot. A schematic would be helpful or we could continue to take your word for things so we can fumble around in the dark for another week or so.
     
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  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Just to add a little to PB's comment, this document describes the marking conventions by TI, note that the device may have been made by National before TI acquired it. Pages 2-4 will be of particular interest: http://www.ti.com/lit/an/snoa039c/snoa039c.pdf

    John
     
  6. Papabravo

    Expert

    Feb 24, 2006
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    Why would you think the chip would work after you let the magic smoke out? How about a schematic so we can help you troubleshoot the problem. You could of course continue to blame everyone else for your problem and you'll have to abandon your project for something simpler.
     
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  7. takao21203

    Distinguished Member

    Apr 28, 2012
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    The pins should never be bent like this.
    In fact the part is not designed for 2.54mm proto PCB.

    There isnt so much business counterfeiting parts costing cents.
    Just urban myth threads.
    The part isnt particulary rare and still in production so who would want to counterfeit it?

    Almost a good one as the free postage post offices in China (they dont exist).
     
  8. gerty

    AAC Fanatic!

    Aug 30, 2007
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    You mean like this?? fake-caps.jpg
     
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