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TPD2S300: Single wire UART protection

Lenio Cacula
Genius 16730 points
Part Number: TPD2S300

I am considering the use of the TPS2S300 into a different application for which it is originally intended. My customer has a single UART line (115kbps, 3.3V) that could potentially be shorted to a 22V line. I thought about using the TPS2S300 for protecting the system. My questions are:

1. Can I combine both CC lines into one and use it as the TX in the UART communication or should I leave one CC line open?

2. Do you see any problems with using this part for this purpose? Do you have a better suggestion?

Thank you!

  • 0
    TI__Mastermind 36756 points
    Hi Lenio,

    I am working to get you in touch with the correct representative for this device. Please allow for some time.

    Thank you,
    Eric
  • 0 in reply to Eric Beljaars
    TI__Prodigy 60 points
    Lenio,

    Key considerations:
    - If customer supplies VM pin with < 8.7V, then the RON of TPD2S300 will change from 1.3Ohm (max) @ 0.49V (low signal) to 18.7Ohm (max) @ 2.45V (should be the same RON max for 3.3V). What is the termination impedance of this UART signal? Is it 50Ohm? If it is 50Ohm, 18.7Ohm (max) may attenuate the signal quite a bit, something to consider. Is it much larger than 18.7Ohm? Then I am not concerned.

    - If customer supplies VM pin with > 8.7V then the RON for each switch is always a low RON, <0.608ohm (max). Even if the system impedance of the UART is 50ohms, I am not concerned with the RON of TPD2S300 here.

    To first order, I would prefer they do not put both switches in parallel, that has not been tested before.

    Thanks,

    Michael Koltun