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Original question:

TS3V713EL: Some questions about TS7V713EL

TS3V713EL: SDA/SCL Internal Pull-up

Matt Qi
Intellectual 2230 points
Part Number: TS3V713EL

Hi team,

I have a question about the TS3V713EL.

Does the SDA/SCL pins have the internal pull-up mechanism?

Looking forward to your reply.

Thanks for your time and effort.

Best Regards,

Matt.

  • 0
    Guru 265990 points

    No. The logic diagram does not have any, and as shown in the typical application diagram, you need external ones.

  • 0 in reply to Clemens Ladisch
    TI__Intellectual 2230 points

    Hi Clemens,

    After testing, it was found that the signal still has a high level on the chip after removing the external pull-up and series resistance.

    Could you please confirm whether there are other circuits inside the chip connected to it that would cause the level of this circuit to be pulled high? Thanks!

    Best Regards,

    Matt.

  • 0 in reply to Matt Qi
    TI__Intellectual 2230 points

    Add the waveform:

  • 0 in reply to Matt Qi
    Guru 265990 points

    When a pin is floating, you cannot measure its voltage.

    Anyway, for the I²C level shifter, it might be possible for the pins to be pulled by the external circuit on the other side.

  • 0 in reply to Matt Qi
    TI__Mastermind 25993 points

    Hey Matt,

    Following up here on Clemens response. First off, he's correct in what he's saying. The pullups are external and there aren't any internal pullups that would hold the line up.

    Why is there concern for this use case? Does the switching and translating work properly when pulled up to 3.3V on one side and 5V on the other? The device isn't made to translate from floating to 5V. That operation doesn't really make sense and I wouldn't be surprised if floating the input causes some corner case anomalies. 
    This could be charge held else where or most likely something pulling up from the other side and behaving this way since you're just floating the input. You could also try putting a pulldown where you removed the  R20295 resistor and see what the results look like? But the most important step here would be the question above. Do the results look normal pulled up to 3.3V?


    -Rami