1N5408 instead of a schottky diode ??

Discussion in 'General Electronics Chat' started by LETITROLL, Feb 5, 2014.

  1. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2
    Is it possible to use 1N5408 diode instead of this schottky diode BYS 045 :

    BYS 045 :

    If = 1.5 A
    Vrpm = 25v to 45v
    Ifsm = 40A
    Vf = 0.50 v
    Tj max = 150 C
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,140
    1,789
    What is the application? The usual reason for using a Schottky diode is the lower forward voltage drop. This parameter is a function of load current so be wary of fixating on a single value. A typical Schottky diode should have a Vf of 0.2-0.3V so I'd be careful of the proposed replacement especially at higher current levels.
     
  3. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2

    Hi papabravo .

    I have an inverter welder , and after replacing a dual diode on it , it has worked for a while and then suddenly , the primary rectifying diodes have all shorted , i don't know why .

    Here is a picture of the PCB , the damage has occured on the chopper/driver area .

    [​IMG]
     
    Last edited: Feb 5, 2014
  4. SgtWookie

    Expert

    Jul 17, 2007
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  5. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2
    I just could not find it , do you have any widely available equivalent to it ?

    BTW is this slight difference in VF @ 1 A representing a big inpact on the circuitry ??
     
    Last edited: Feb 5, 2014
  6. Denesius

    Member

    Feb 5, 2014
    89
    14
    A quick check revealed your diodes as available from Mouser.com for (are you ready for this?) as little as 17 cents each!
     
  7. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2
    You don't get the point , i don't have the time to order it online right now , and if i do , i will have to wait 15 days , am looking for another equivalent , not specifically SMD type , just a schottky diode that would do the same job as the original , i cant find any on the net thats why i asked here , maybe some one has experience with this type of diodes .
     
  8. crutschow

    Expert

    Mar 14, 2008
    13,002
    3,229
    If you can't order one, then what type of Schottky diodes do you have available to purchase or use? Where do you buy/get your devices?
     
  9. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2
    I buy my components from a electronics selling store , but the seller doesn't have a big knowledge on components specs , thats why i want to get some information here , and see what diodes would make a close match to the original one , am pretty sure the store will provide at least one of those matchs .
     
    Last edited: Feb 5, 2014
  10. MrChips

    Moderator

    Oct 2, 2009
    12,440
    3,360
    Everybody has BYS10-45.
    Newark and Digikey will ship same day.
    Newark has them for $0.09 each.
     
  11. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    The main issue in that application is diode speed.

    The IN5408 is hundreds of times too slow, and will cause problems and fry itself. And possibly fry other parts.

    Like everyone has said; just order the correct part. :)
     
  12. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2
    Nice answer .
     
  13. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
    783
    Probably not if its in a SMPSU!

    There's such thing as a UF5408 - not as fast as SB and greater Vf.
     
  14. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
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    You'll have all the time in the world to sit and twiddle your thumbs after excessively slow rectifiers cause the rest of the circuit to burn up.
     
  15. crutschow

    Expert

    Mar 14, 2008
    13,002
    3,229
    Then you have a little work cut out for you. Since there are likely many Schottky diodes that would meet you spec, you need to determine all the diodes he has and then look them up to see which may be Schottkys that meet or exceed you requirements.

    Alternately you can look up Schottkys in a supplier website such as Digikey or Mouser and find whatever suitable Schottkys they sell, which are probably those commonly used, and see if your supplier has any of those.

    None of us likely know what Schottkys are most commonly used, we would just have to do the grunt-work to determine that, and you are in a better position to do that then us. :rolleyes:
     
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