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ISO721 about Tx Distance

Jin Kyung Han
Expert 1520 points
Other Parts Discussed in Thread: ISO721

Hello

I would like to know the transmission distance of ISO721.

One of customers in IP Camera industry is going to use the ISO721 to send data with long distance cable.

If it is not possible, should we use it with RS422/485 etc?

Except speed and immunity high voltage surge, what is different things between Photo coupler and ISO721?

Please let me know.

Thanks and Best Regards  

  • 0
    TI__Intellectual 2200 points

    Jin Kyung,

    ISO721 can drive a 15pF output load. So you can use it to drive about 4 to 6 inches (thumb rule: 3pF/inch) of board trace. For long cables, yes, RS485 is a good choice. TI has isolated RS485 devices available:

    http://www.ti.com/lsds/ti/isolators/isolated-rs-485-products.page?paramCriteria=no

    Some benefits of digital isolators vs. opto couplers: high speed and low propagation delays, lower power (no LED drive current), stable characteristics over lifetime (no LED aging effect), multi-channel configurations with good matching, integration in isolated functions (for eg. isolation+rs485), better common mode immunity.

    Rgds,

    Anant

  • 0 in reply to Anant Kamath
    Expert 1520 points

    Agant

    Thank you for supporting, We cleared the issue.

    Thanks