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Original question:

DS90UH940-Q1: input signal spec (RINx pin)

DS90UH940-Q1: input signal spec (RINx pin)

Nao
Genius 4905 points
Part Number: DS90UH940-Q1
Other Parts Discussed in Thread: ALP

Hi, E2E members

I have questions about between FPD-Link output and input jitter spec.

DS90UH929 datasheet says FPD-Link output jitter is 0.3UI(Typ).

On the other hand, the following E2E says DS90UH940's FPD-Link input jitter is 0.3UI(Max) .

e2e.ti.com/.../733562

No margin for connecting DS90UH929 and DS90UH940.
How should I think about that?

Regards,
Nao

  • 0
    TI__Expert 4555 points

    Hi Nao,

    This is a very valid concern, and the best way to go about this would be to measure the output jitter for the 929 to see if it is consistently under 0.3UI. You can then link it up to the 940 and perform tests on lock consistency.

    The DS90UH940 datasheet does say that it should be compatible with the DS90UH929/947/949. I saw with all these devices, they were characterized with 0.3UI (typ) as well. We haven't seen many issues with pairing these SerDes together, but please let us know if you begin experience trouble with it.

    I will try to escalate the issue that the Input/Output jitter tolerance specs can be confusing and may lead to concern that there is not enough margin for jitter. 

    Regards,

    Jonny

  • 0 in reply to Jonathan Nguyen
    TI__Expert 4555 points
    Nao,

    You can also use the margin analysis function within ALP. This can give you a comprehensive view of the link margin in the system.

    Regards,
    Jonny
  • 0 in reply to Jonathan Nguyen
    Genius 4905 points

    Hi, Jonny

    I will tell my customer to your answer.
    I will ask you again, if my customer have some more questions.

    I would like to use the margin analysis function.
    So, How do I use it? Do you have some material?

    Regards,
    Nao

  • 0 in reply to Nao
    Genius 4905 points
    Hi, Jonny

    Our customer says that we can't estimate the impact of noise of cable and transmission path in this spec,
    because there is no margin between output and input of FPD-Link line.

    Could you reconfirm about the input jitte spec of DS90UH940 (0.3UI:Max)?
    This spec of DS90UB927/928 is output jitter 0.29UI(Max) and input jitter 0.35UI(Max).
    I think it is reasonable. Can you relax this spec in DS90UH940?

    Regards,
    Nao
  • 0 in reply to Nao
    Genius 4905 points
    Hi, Jonny

    Sorry to rushing you up.
    Do you have any comment about this?
    My customer are waiting for the reply.

    Regards,
    Nao
  • 0 in reply to Nao
    TI__Expert 4555 points

    Nao,

    This isn't necessarily a spec that we can relax, as it is how the validation team decided to characterize these specifications.

    As for the margin analysis tool, please look at this thread: e2e.ti.com/.../732296

    If you need the scripts to set up the margin analysis (they should be included in the ALP Scripts folder), I can send them to you offline.

    Regards,

    Jonny

  • 0 in reply to Jonathan Nguyen
    Genius 4905 points
    Hi, Jonny

    Thank you for your quick feedback.
    Please send me the scripts. How do I tell you my e-mail address?

    Regards,
    Nao
  • 0 in reply to Nao
    Genius 4905 points

    Hi, Jonny


    Regards,
    Nao

  • 0 in reply to Nao
    Genius 4905 points

    Hi, Jonny

    The attachment file may have been rejected in our e-mail system.
    Hence, please let me know by this thread, if you send me to the scripts by e-mail.

    Regards,
    Nao

  • 0 in reply to Nao
    Genius 4905 points
    Hi, Jonny

    Do you have any update?

    Regards,
    Nao
  • 0 in reply to Nao
    TI__Expert 4555 points

    Nao,

    Do you have an FAE that works with you? I am unable to share the script on a public forum.

    Regards,

    Jonny

  • 0 in reply to Jonathan Nguyen
    Genius 4905 points

    Hi, Jonny

    Please send it .
    I will tell you again, if we can’t get the script.

    Regards,
    Nao

  • 0 in reply to Nao
    Genius 4905 points
    Hi, Jonny

    Do you have any update?

    Regards,
    Nao
  • 0 in reply to Nao
    TI__Expert 4555 points
    Nao,

    I am unable to directly send you a script offline. Please contact your local FAE and he/she will forward the scripts back to you. The scripts should also already be included within the scripting folder of the device profile. If it is not there, download the device profile update found on this webpage: http://www.ti.com/tool/ALP

    Regards,
    Jonny
  • 0 in reply to Jonathan Nguyen
    Genius 4905 points
    Hi, Jonny

    Thank you for your reply.

    Regards,
    Nao