SMD Code question

Discussion in 'Power Electronics' started by razirafi, Sep 23, 2017.

  1. razirafi

    Thread Starter New Member

    Aug 26, 2008
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    Hello, I am currently trying to fix my CTEK MXS 5.0 charger that died on me. I have already identified a shorted SMD MosFET and am trying to decode another part which looks like a SOT223-4 device. The markings on this device looks like a D1131G or D113iG, and below that are the numbers 17-50. I tried searching online for information to no avail. The Aliexpress site shows a SOT223-4 part which it labels as an IC with the model number 17-50, but indicates it as "no longer available". May I humbly ask for help from anyone who knows what part this is?
     
  2. ian field

    AAC Fanatic!

    Oct 27, 2012
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    They do occasionally put "real" codes on the not so tiny SMDs, and the Asian codes are always cropped - look up 2SD1131 and see if it makes any sense.

    Guessing games aren't exactly rare!
     
  3. ScottWang

    Moderator

    Aug 23, 2012
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    When I googled "D1131" then it is very easily to get more spec info, but when I googled "D113i" then I can't get anything, so the id can't be "D113i", and I think the id number is 2SD1131.
     
  4. ian field

    AAC Fanatic!

    Oct 27, 2012
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    Not guaranteed - but a possibility worth investigating.
     
  5. ScottWang

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    If you check the id number of transistors then you will find out that there is no two English alphabets after the id numbers, almost only one English alphabets whatever they are three Arabic numerals or four Arabic numerals, so I would rather to believe that it is 2SD1131.

    2sd transistor.
     
  6. SLK001

    Senior Member

    Nov 29, 2011
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    I agree with Scott that it is an NPN power transistor (by the 2SD prefix) in what looks to be a SOT-89 package. I would concentrate my search using 2SD1131 as my starting point.
     
  7. razirafi

    Thread Starter New Member

    Aug 26, 2008
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    Thank you all for your reply. I did think about the 2SD1131 but just needed to ask for any opinions about the coding. I will check out the datasheet and go from there. I see no harm in trying it out and if it fails and do more damage to the circuit, then it's OK as it has been damaged already to begin with.
     
  8. ian field

    AAC Fanatic!

    Oct 27, 2012
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    Good thing I suggested looking up the 2SD1131 then wasn't it..................
     
  9. ScottWang

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    Aug 23, 2012
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    The symbol looks like "D113iG", but I think probably it is 2SD1131G, when I used "2DS113iG" to googled it, but I can't get anything, and I just used "D113i" to googled it then I got :
    Combination of symbols starting D113I
    The transistor D113I is a discrete electronic device that performs a single transistor function and is composed of many elements being structurally an integrated circuit, for example, a compound transistor or a lot of high power transistors. Transistors are divided into two classes that are different in structure, operating principle and parameters, i.e. bipolar and field-effect (monopolar) ones.

    I can't make sure that it is D113i, the id number still a mystery.
     
  10. razirafi

    Thread Starter New Member

    Aug 26, 2008
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    Ok, I have cleaned the part surface and took more detailed photos.
     
  11. ian field

    AAC Fanatic!

    Oct 27, 2012
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    Must've been a pretty impressive phut - looks like a heat sink tab was blown out of its solder mount.

    Hard to tell right next to the crack, but that "D" might actually be a stylised trade mark.

    I wouldn't put it past that number being a house code.

    A bit of hand tracing might be needed to figure out what it used to be. Some ESR meters will display very low DC resistances and most will ignore semiconductor junctions. Quite handy for tracing hidden tracks in multilayer boards.
     
  12. razirafi

    Thread Starter New Member

    Aug 26, 2008
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    That part was actually still intact but when I tried to remove it, I first lifted the two outer legs and then when I started lifting the center leg that is when the tab broke the epoxy casing. The center and right leg showed continuity on my DMM so I thought it has shorted out.
     
  13. razirafi

    Thread Starter New Member

    Aug 26, 2008
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    Finally found it..It is the AP1117 by Diodes Inc. (please see page 8).
    Thanks to all who shared their insights and for generally helping out to identify this part.
     
    Last edited: Sep 25, 2017
  14. ScottWang

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    Aug 23, 2012
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    Found out is great, the left three symbols are correct, but how did you know that it is the id number?
     
  15. razirafi

    Thread Starter New Member

    Aug 26, 2008
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    Actually I did not know that it was the ID number. I just followed up on my initial lead from the Aliexpress site which listed a 17-50 part but at the same time listed it as no longer available. I was a bit desperate so I just googled all possible iterations of the code as I could think of. The first datasheet that looked promising was the AP1117 by Anachip so I kept on checking out other datasheets. When I came across the Diodes Inc. datasheet, voila, exact markings. It is also the same as the AMS1117 by Advanced Monolithic Systems. I am posting the datasheets for comparison.
     
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