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Hot swappable I2C driver that can drive 200 meters of cable

Hoshang Vaid
Prodigy 20 points
Other Parts Discussed in Thread: TCA4311A, P82B96, TCA9617A, TCA9517

I am looking for a Hot swappable I2C driver that can drive 200 meters of cable. TCA4311A was recommended because it is Hot swappable but it does not specify a length of cable that can be driven.  It mentions that it can drive 1 nF.  Do you know if this device can drive 200 meter cable and if you have a recommendation for a cable that  can be used, I would appreciate the information. 
If this is not possible, I wold appreciate any other ideas.

Thanks.

  • 0
    TI__Genius 16510 points
    Hello Hoshang,

    Thanks for the question.

    Can you point to where in the datasheet you see this mention of 1 nF capacitance limit?

    The main thing that makes this device hot-swappable is that it will not connect the two sides of the I2C bus until it detects that both sides are idle.

    If this is a requirement, then the TCA4311A is currently our only device supporting hot swap capabilities like this. If your setup can handle data glitch during a the event of a slave connecting to it, then our repeaters can handle a hot connect event.

    I don't believe 1nF or even 4nF (in the case of the P82B96) will be capable of driving a 200 m cable. The capacitance varies significantly by cable, but I've never seen a cable this long able to hit that low of a capacitance (if you do manage to find one, please share!).

    I believe you will need to go with multiple I2C buffers and repeaters in series in order to achieve 200m cable length (essentially splitting the load into smaller segments).

    It would be possible to attempt this with multiple P82B96 or a few TCA9617As (I suggest TCA9617A over TCA9517 because it has smaller propagation delays, which will be critical to your communication speed supported by such a large length of cable)