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TCA9617A: Buffered low feature, preventing the lockup condition

FARMAN ULLAH
Prodigy 140 points

Part Number: TCA9617A

Hi All,

I2C repeaters which incorporate static or dynamic offset voltage, how these devices do not recognize buffered low signal as a valid low? what is the the valid voltage range or how high/low the "buffered low" signal could be so that it is not recognized as a valid low signal?

Thanks

  • 0
    Prodigy 140 points

    Thanks. The TCA9617A/B has the minimum voltage of the buffered low signal, which is 0.5V, I would like to know how high it could be as an application point of view that it is ignored/not considered as a valid low when the B-side I/O is driven low internally?

  • 0 in reply to FARMAN ULLAH
    TI__Guru 53535 points

    Hi Farman,

    The B-side of TCA9617A, which has the buffered low, specifies its high- and low-level input voltage thresholds as well as the output low-level output voltage in Section 6.5 of the datasheet. 

    As you stated, the output voltage is higher than the input voltage threshold in order to avoid any system lock-ups. Any device driving a low to the B-side of this device will need to be capable of driving below the 0.4V level in order for TCA9617A to recognise the signal.

    Let me know if this is clear and if you have any more questions.

    Regards,
    Eric Schott

  • 0 in reply to Eric Schott1
    Prodigy 140 points

    Thanks Eric, Appreciate your reply.

    It means that driving a low to the B-side, would have the voltage level anywhere between 0 and 0.4V in order for the TCA9617A to recognize the signal, is this correct?

    It will not be a hard low as in the case of A-side

    -Farman

  • 0 in reply to FARMAN ULLAH
    TI__Guru 53535 points

    Hi Farman,

    I believe your understanding is correct. Any device driving a low signal to the B-side of TCA9617A will need to drive lower than 0.4V. TCA9617A itself will not drive below this voltage, and it's output voltage will be in the 0.48V and 0.58V range (while remaining within the specified output current values).

    The A-side does not have this functionality, and can be treated as a standard I2C connection.

    Regards,
    Eric Schott

  • 0 in reply to Eric Schott1
    Prodigy 140 points

    alright, thanks a lot.