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DALI TX opto should have higher CTR?

Discussion in 'Microcontrollers' started by Flyback, Dec 6, 2017.

  1. Flyback

    Flyback Well-Known Member

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    Hello,
    Figure 5, page 3, of the following DALI application note (AN1465) shows optos being used to isolate both TX and RX DALI signals…. [​IMG]

    AN1465 Application note:
    http://ww1.microchip.com/downloads/en/AppNotes/01465A.pdf

    Though surely, the TX opto should be a TCLT1009 (CTR of TCLT1009 = 300%) and not a TCLT1000 (CTR of TCLT1000 = 50%)? [​IMG]

    Also, surely the RX opto should be a TCLT1000, which it indeed is. [​IMG]

    The reason that the RX opto should be a TCLT1000 is because it has a lower capacitance seen at its emitter pin which means the rise time of the emitter can be quicker. Do you agree? [​IMG]

    TCLT100X opto datasheet:
    https://www.vishay.com/docs/83515/tclt1000.pdf
     
  2. be80be

    be80be Well-Known Member

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    Don't look like it would matter the TCLT1000 would work fine for both as shown.
     
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