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DS90UB913A-CXEVM: 1.8V versus 3.3V selection

npb17
Expert 1615 points
Part Number: DS90UB913A-CXEVM

The DS90UB913A eval board has jumpers for 3.3V and 1.8V selection.

Which way should the jumpers be if I want to provide 1.8V input on the serializer JP1 pins?  Please provide guidance on setting JP13 and JP8 since the user manual is not clear (just says "selects 3.3" or "selects 1.8"...)  Should I put JP13 on the 0V side for 1.8V input?  Or leave the jumper off completely?

Last question: can I provide 1.8V input to the serializer, with 3.3V output on the deserializer, and power over coax with 5V at the DEserializer?

  • 0
    TI__Genius 12866 points

    Hi Nick,

    From my understanding, you would like to have VDDIO=1.8V instead of 3.3V. If so,

    The JP8 jumpers are used to power VDDn pins. Please leave it as illustrated in users manual. 

    The JP13 jumpers are used to select VDDIO level. You need to remove the jumper cap, and externally supply 1.8V to pin 2(the center pin) to get VDDIO=1.8V.

    I am not quite following on your last question. If you are using a DS90UB914A EVM as your deserializer and using Power over Coax configuration. You should provide 5V input to the deserializer only.  Supply for VDDn pins should always be 1.8V and you can choose to have 3.3V or 1.8V supply to VDDIO. 

    Sincerely,

    Charley Cai

  • 0 in reply to Charley Cai
    Expert 1615 points

    Hi Charley,

    Thanks.  That mostly answers my questions.

    To clarify the last one:  I am planning to do like you said...5V to the deserializer and power for serializer over coax only. 

    That said, which of the following configurations will work properly?

    • 1.8V VDDIO on serializer, 3.3V VDDIO on deserializer
    • 1.8V VDDIO on serializer, 1.8V VDDIO on deserializer

    Are VDDIOs isolated so that either board can run either IO standard?

    -Nick

  • 0 in reply to npb17
    TI__Genius 12866 points

    Hi Nick,

    Your understanding is correct. VDDIO is isolated between boards. You can choose to run either IO standard on one board. 

    Both configurations listed should work.

    Sincerely,

    Charley Cai