opto something Liteon 816A4

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  • jm1234
    Senior Member
    • Jan 2024
    • 59
    • Slovakia
    #1

    opto something Liteon 816A4

    Hi,
    I'm troubleshooting a power supply board and one opto coupler seems shorted. It's a through-hole, marked with 3 lines:
    1223
    816A4
    W
    I'm not sure what replacement to buy for it. It resembles LTV-816 (https://www.tme.eu/sk/en/details/ltv...output/liteon/), but I'm not sure it's 100% that. The data sheet shows multiple sub-types like 816M, 816S, but 816A is not there.
    I do have other functional pieces on the same board, so I could do some measurements on those, but I'm not sure what to check.
    Any idea appreciated.
    Tags: None
    • harp
      Badcaps Veteran
      • Jun 2022
      • 592
      • Planet Earth
      #2
      When you desolder optocoupler from board, so it is off circuit, check in diode mode between leg#1 and 2, an later betveen leg#3 and 4 on optocoupler in both direction.
      Whats is readings?

        Comment

        • jm1234
          Senior Member
          • Jan 2024
          • 59
          • Slovakia
          #3
          0 resistance between 1 and 2, that's why I wrote it's shorted. My question was more to what could I replace it with.

            Comment

            • harp
              Badcaps Veteran
              • Jun 2022
              • 592
              • Planet Earth
              #4
              I dont know for sure. Some standards are 817, so may or may not be critical for choosing 816 instead by design.
              Here is compare, a few point is different.
              https://www.utmel.com/compare/HCPL-8...V-816--4824806

                Comment

                • truclacicr
                  Badcaps Veteran
                  • Apr 2019
                  • 289
                  • australia
                  #5
                  I think you are misinterpreting the datasheet.
                  LTV-816 comes in a DIP (page 2)
                  LTV-816M is a wide lead spacing package
                  LTV-816S is a surface mounting package


                  "A2" is the rank (page 3),

                  Rank mark "A" denotes a CTR (current transfer ratio) of 80 - 160. (page 10)

                  https://www.tme.eu/Document/5aee6f35...fd/LTV-816.pdf

                    Comment

                    • jm1234
                      Senior Member
                      • Jan 2024
                      • 59
                      • Slovakia
                      #6
                      You're probably right in that, but there is no way to order specific rank as far as I can tell, so that seems puzzling. Anyhow, I ordered that LTV-816 from TME and what arrived is labeled 816B. I put it on the PCB and the issue is gone now. So I consider this a success, knowing well it's too soon to claim any victory here.

                        Comment

                        • truclacicr
                          Badcaps Veteran
                          • Apr 2019
                          • 289
                          • australia
                          #7
                          The ordering information is towards the end of the datasheet.
                          Attached Files

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