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Default state of TCA5405 outputs...

Soren Steen Christensen
Genius 3685 points
Other Parts Discussed in Thread: TCA5405

Hi TI E2E Support,

Reading through the datasheet for the newly introduced TCA5405 the reset state of the 5 outputs unfortunately isn't clear to me.

Do the outputs startup being all 1) low, 2) high, 3) undefined? I hope somebody can clarify on this?

Best regards and thanks in advance
  Søren

  • 0
    TI__Prodigy 210 points

    Hi Soren,

    The default state of the outputs on power-up is Low.   Thanks for pointing this out, we will clarify this in the datasheet.

    Best regards,
    Mark

     

  • 0 in reply to Mark Welty
    Genius 3685 points

    Hi Mark,

    No problem - You are welcome - Thanks for fast feedback - Exactly what I needed - Thanks
      Søren

  • 0 in reply to Soren Steen Christensen
    Genius 3685 points

    Hi Mark and TI e2e support,

    I do now have an additional question to this one, with which I hope you can heop me forward?

    In the datasheet page 3 it's stated that tPER should be between 0.001 and 10ms. Further down in the same table fMIN and fMAX are given to 1MHz and 10kHz (seems swapped?).

    The 1MHz correspond nicely to the 0.001ms, but the 10kHz doesn't correspond to 10ms. 

    Which is right value - 10kHz or 10ms? In case it's allowed to go as low as 100Hz (=10ms) is it still a requirement to have 100ns edges, or could this be relaxed for this slow communication rate?

    I hope the question is clear? Best regards and thanks

      Søren

  • 0 in reply to Soren Steen Christensen
    TI__Intellectual 1930 points

      Søren,

    Thanks for pointing out this erro in the DS. The correct value is 100hz (10ms). We will make this change on the web asap.

    Regards,

    Akhil.

  • 0 in reply to Akhil Nair
    Genius 3685 points

    Hi Akhil,

    Thanks for your feedback. I'm sorry for this late response, but I somehow missed the feedback email and thereby didn't saw your reply prior to now. The 100Hz is however great news to get officially confirmed - Thanks :-). Did you as well get a chance to check up on if the 100ns edge requirement can be relaxed in this scenario or if this is design bound despite the actual frequency being used for communication?

    Reason for asking is that I'm currently running the setup with much slower edges (like 10-50us AFAIR) and it seems to work pretty stable, but I would like to get some assessment if this is allowed or not (when using 1ms pulses for communication)? 

    Best regards and Thanks again 

      Søren