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DS90UB960-Q1: About the application of ds90ub960 and ds90ub953?

Tonyx.wu
Genius 4015 points
Part Number: DS90UB960-Q1

About the layout cabling of ds90ub960 and ds90ub953, I have a few questions to ask. Different materials on the official website have different opinions. I mainly want to confirm which method is the most beneficial to EMI and EMS. Thank you!

1. Is it better to route fpdlink from connector to AC coupling capacitor according to single ended 50ohm or with rin- according to differential 100ohm?

2. Is it better to use single ended 50ohm or differential 100ohm wiring between AC coupling capacitor and chip?

3. Is the AC coupling capacitor close to the connector or the chip end

4. We have added high-voltage ESD devices at the connector end. Is it necessary to add or reserve low-voltage ESD devices at the device end

  • 0
    TI__Mastermind 25301 points

    Hi Tony,

    Thanks for your inquiry. Let me discuss this quickly with my colleagues and get back to you with feedback early next week.

    Best,

    Thomas

  • 0 in reply to Thomas Bejin
    TI__Mastermind 25301 points

    Hi Tony,

    Thanks again for your inquiry and appreciate your patience waiting for a response here. Included my feedback below:

    Tonyx.wu said:
    1. Is it better to route fpdlink from connector to AC coupling capacitor according to single ended 50ohm or with rin- according to differential 100ohm?
    • Do you know if a coax cable or STP cable is used in this system? If coax is used, single ended 50 ohm traces should be used on both RIN+ and RIN- with spacing greater than 3x trace width. If using STP, differential 100 ohm should be used.
    Tonyx.wu said:
    2. Is it better to use single ended 50ohm or differential 100ohm wiring between AC coupling capacitor and chip?
    • This depends on the cable which is used in this application. If a coax cable is used, recommend single ended 50 ohm traces between the AC coupling capacitor and the the SER/DES
    Tonyx.wu said:
    3. Is the AC coupling capacitor close to the connector or the chip end
    • The AC coupling capacitor should be included as close to the SER/Des as possible
    Tonyx.wu said:

    4. We have added high-voltage ESD devices at the connector end. Is it necessary to add or reserve low-voltage ESD devices at the device end

    • In our serializers and deserializers there is included ESD protection circuitry, if additional protection is desired this may be added between the AC coupling capacitor and the Rx/Tx pin of the DS90UB960 / DS90UB953

    For additional background, the High Speed Layout Guidelines (Rev. A) application note is available on TI.com which details some best practices for high speed layout. 

    Let me know if there's any more background on this I can help with!

    Best,

    Thomas