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TLK2711EVM-CVAL: TLK2711EVM schematics clarifications

Jayshree Rapha
Prodigy 10 points

Part Number: TLK2711EVM-CVAL
Other Parts Discussed in Thread: TLK2711-SP

I am designing a SerDes interface using TLK2711-SP and referring to this EVK schematic: /cfs-file/__key/communityserver-discussions-components-files/138/5775.HREL002A_5F00_SCH.pdf

  1. Is it recommended to have 10K pull up on all TXD lines?
  2. Are any series resistors recommended on any pins?
  3. 0.01uF caps near serial data connectors, what if no dedicated connectors are used for each data line. Can those caps be omitted or is it recommended on VDDA1 line
  4. Is filter recommended (VDD --> VDDA1) irrespective of the power source?
  5. Are external pull-up and pull-down recommended? Datasheet mentions internal 10K pulls on ENABLE, LCKREFN, LOOPEN, PRE, PRBSEN, TKLSB, TKMSB, TESTEN

Awaiting your response

  • +1
    TI__Guru**** 162861 points

    Hi Jayshree:

    Jayshree Rapha said:
    Is it recommended to have 10K pull up on all TXD lines?

    If TXD is not used, it's better to pullup or pulldown TXD pin. 

    Jayshree Rapha said:
    Are any series resistors recommended on any pins?

     no series resistors recommended on any pins.

    Jayshree Rapha said:
    0.01uF caps near serial data connectors, what if no dedicated connectors are used for each data line. Can those caps be omitted or is it recommended

    C25 is needed no matter with connector or not, C38 is not needed if without connector.

    Jayshree Rapha said:
    Is filter recommended (VDD --> VDDA1) irrespective of the power source?

      yes

    Jayshree Rapha said:
    Are external pull-up and pull-down recommended? Datasheet mentions internal 10K pulls on ENABLE, LCKREFN, LOOPEN, PRE, PRBSEN, TKLSB, TKMSB

    not all these pins has internal pullup, ENABLE  and LCKREFN pins have internal pulldown resistors.

    Best

    Brian

  • 0 in reply to Brian Zhou
    Prodigy 10 points

    Thanks Brian.

    Also, Enable and Lockrefn have internal pull-up right?

    Brian Zhou said:
    not all these pins has internal pullup, ENABLE  and LCKREFN pins have internal pulldown resistors.

     

    So, should I add

    external 4.7K pull-up resistors for ENABLE, LOCKREFN

    external 10K pull-down resistors for LOOPEN, PRE, PRBSEN, TKLSB, TKMSB

  • 0 in reply to Jayshree Rapha
    TI__Guru**** 162861 points

    Sorry, my mistake, there is no need to add external resistors for 

    external 4.7K pull-up resistors for ENABLE, LOCKREFN

    external 10K pull-down resistors for LOOPEN, PRE, PRBSEN, TKLSB, TKMSB.

    Regards

    Brian