This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ISO1640-Q1: Can I use ISO1640-Q1 for automotive UART communication?

Part Number: ISO1640-Q1
Other Parts Discussed in Thread: ISO7721-Q1, ISO6721-Q1, , ISO6721, ISO7721, ISO1640

Hello team,

My customer is looking for UART isolator.

I cannot recommend digital isolator such as ISO6721-Q1, ISO7721-Q1 because customer wants bi-directional isolator.

I see TI has I2C isolated interface named ISO1640-Q1.

Can I use this for UART communication?

Based on my understanding, the only difference between UART and I2C is necessity of clock synchronization or not.

Thanks for you help.


Oliver Kim

  • Hi Oliver,

    Thank you for posting to E2E! Although ISO164x devices could be used to isolate CMOS signals, data flows bidirectionally in UART from TX of one device to RX of another. I suspect ISO6721 or ISO7721 is the right device for our customer to use in a configuration similar to the schematic shown below:

    Please check with our customer that this is the solution they'd like to replicate, and let us know if there are any further questions.

    Thank you,
    Manuel Chavez

  • Hello Manuel,

    I don't understand what you mean.

    The reason why I recommend ISO1640-Q1 is it supports bi-directional communication in "1-wire", not separate RX and TX.

    1-wire should be both input and output.

    Please refer to the example. (

    Customer cannot use ISO6721-Q1, ISO7721-Q1 because there is only one wire which is used for both TX and RX.

    I believe ISO1640-Q1 is the only one option that we can suggest in 1-wire bi-direction application. Is it correct?



    Oliver Kim

  • Hi Oliver,

    Thank you for clarifying the 1-wire UART requirement. ISO1640 is our best option here since it isolates bidirectional communication. If our customer's system supports open-collector inputs and outputs, has data rates below 1.7MHz (both look typical in the example you provided), and is compatible with ISO1640's VIH/L and VOH/L thresholds shown below, it should be fine to use with "1-wire" communication:

    Manuel Chavez