• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 34 subscribers
  • Views 756 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

Original question:

DS90UB954-Q1EVM: REV E2, STP connection

DS90UB954-Q1EVM: REV E2, STP connection

paulmcw
Intellectual 295 points

Part Number: DS90UB954-Q1EVM
Other Parts Discussed in Thread: DS90UB954-Q1

Hi,

How can I tell which version of DS90UB954-Q1 EVM I have? I don't see a Rev indication on the PCB.

Datasheet Gerber files show that there is a significant length mismatch between the signals to RX0n and RX0p - which would seemingly preclude high speed differential operation.

Would I be correct in assuming that the version I have is not suitable for STP and that mismatch has been corrected in Rev E2?

Regards

Paul

  • 0
    TI__Genius 10475 points
    Hello,
    The 953 and 954 EVM's are designed to work with coax and not STP. You would need another connector on the board with proper differential routing for the P and N terminals to use it for STP.
  • 0 in reply to Palaniappan Manickam
    Intellectual 295 points
    I understand that as delivered the EVM is not suitable for STP.

    However, in a related thread it is pointed out that with the correct version of EVM and by fitting a FAKRA connector at RX0n STP operation is supported.

    My question was how to determine the version of EVM. On the version I have the different routing lengths from DS90UB954 to RX0n and RX0p would seem to mean that differential operation cannot be supported. Has this been corrected in Rev E2?

    Regards Paul
  • 0 in reply to paulmcw
    TI__Genius 12705 points
    Hello,
    The prototype revision EVM had vertical mount connectors and did not have RX0 + brought to edge of the PCB.
    Any length mismatch could be corrected by designing an interface PCB from 2x Fakra to STP connector.

    Regards,
  • 0 in reply to Liam Keese
    Intellectual 295 points

    If I understand correctly the board I have - which has RX0+ brought to the edge although the FAKRA connector is not populated - is a Rev2 EVM and is described as being suitable for STP.

    The requirement to design a pcb to compensate for the length mismatch seems excessive for the simple demo I was planning.

    Can you confirm that this length correction is necessary and based on the layout can you let me know what the correction value is?

    Thanks

    Paul