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DS90UB935-Q1: FPD link III - CMLOUT eye diagram

Stijn Bosmans
Prodigy 225 points
Part Number: DS90UB935-Q1
Other Parts Discussed in Thread: DS90UB954-Q1,

Hi all,

In our design we are using the DS90UB935-Q1 FPD link serialilizer. To determine the signal quality of the design I want to use the CMLout function of a deserializer(DS90UB954-Q1 evm). 

The goal is to measure an eye-diagram at the CMLOUT of the deserializer. I was looking to draw a mask for this eye diagram, unfortunately I wasn't able to draw an eyediagram with the datasheet information.
While I was looking for this I found this topic: https://e2e.ti.com/support/interface/f/138/t/766950?tisearch=e2e-sitesearch&keymatch=FPD%20eye
In the limit calculations that are done in the excel file shared in this topic, there are two parameters mentioned that I can't find the datasheet of the used serializer (tLHT from Serializer Datasheet and tHLT from Serializer Datasheet).
Can you please share these parameters with me? Or please provide feedback how I should calculate the limits for the mask(in the eyediagram)?

Thanks,
Stijn

  • 0
    TI__Guru** 107510 points
    On the 954, a CMLOUT eye opening of at least 0.45 UI suggests that the forward channel signal integrity is likely acceptable. However, further testing such as BIST is recommended to verify error free operation. An eye opening of less than 0.45 UI indicates possible issues with the forward channel signal integrity.
    The amplitude on the Rx side is not critical as there is limiting amplifier function in the Rx chain.
  • 0 in reply to Hamzeh Jaradat
    Prodigy 225 points
    Hi Hamzeh,

    Thank you for your replay, I will look into the BIST function as well to verify the signal integrity.

    Thanks,
    Stijn