• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 563 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.

DS90UB935-Q1: input eye diagram test

Sherry Liang
Genius 10255 points
Part Number: DS90UB935-Q1


Dear team,

My customer is testing the signal quality of 935's input MIPI CSI. Do we have any requirements for eye height, eye width and jitter? I didn't see the requirements in our datasheet.

Thanks & Best Regards,

Sherry

  • 0
    TI__Mastermind 30770 points

    Hi Sherry,

    Our 935 device is compliant with the MIPI D-PHY v1.2 and CSI-2 v1.3 specifications. In the 935 datasheet, we have the expected CSI-2 LP to HS Mode Transition in Section 8.2.3 Application Curve and specific electrical characteristics in the Section 6.5 Electrical Characteristics table.

    In terms of eye height, eye width, and jitter, these are requirements for the FPD-Link channel that are defined in the deserializer datasheet and measured using the CMLOUT pins on the paired deserializer. I recommend checking the deserializer datasheet for these values.

    Best,

    Justin Phan

  • 0 in reply to Justin Phan
    TI__Genius 10255 points

    Hi Justin,

    Thanks for your reply!

    In 960 datasheet, there are eye open width and input jitter spec, but I don't find eye height. Could you please help check it?

    Thanks & Best Regards,

    Sherry

  • +1 in reply to Sherry Liang
    TI__Mastermind 30770 points

    Hi Sherry,

    There is no need to qualify the eye height from CMLOUT since CMLOUT is a limiting amplifier anyways. The eye height doesn't tell you about the margin of the received signal. It is just for identifying gross issues with the signal quality.

    The MAP tool should be used for qualifying the link margin in the system instead. Here is the guide to the MAP tool:

    https://www.ti.com/lit/ug/snlu243/snlu243.pdf?ts=1647962794797&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FDS90UB960-Q1 

    We do not have a pass/fail criteria for CMLOUT. It is only used for gross level issue debugging. The MAP tool is what we recommend for making a pass/fail assessment for the margin. 

    Best,

    Justin Phan