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DS90UB948-Q1: DS90UB948：The reason for the recommended values in MAP

?? ??
Prodigy 140 points
Part Number: DS90UB948-Q1

Tool/software:

Hi,

In the explanation document for MAP, the recommended values for MAP are described as "having three or more consecutive EQ values and four or more consecutive SP values in green."

1. "Three or more consecutive EQ values in green" - Why is it three? I assume it is to have a margin against cable deterioration, but please explain the basis for the number three.
2. "Four or more consecutive SP values in green" - Why is it four? Please explain the basis for the number four.
3. Which range of SP is indicated by the red arrow or the orange arrow in the diagram? Since everything is green in MAP, I think it is not the red range.
4. When only four SP values are green, will the eye pattern overlap with the mask? Or is the limit of not overlapping with the mask set at four SP values?

Best,

  • 0
    TI__Mastermind 37370 points

    Hi.

    Let me look into this and review the app note. I will get back with you by tomorrow.

    Aaro

  • 0 in reply to Aaron Heng
    Prodigy 140 points

    Hi,

    How is the investigation going?

    If there is any information that has been revealed, even if it's partial, I would like to know.

    Best,

  • 0 in reply to ?? ??
    TI__Mastermind 37370 points

    Hi,

    Sorry for the delayed. The SP values provide the proper timing offset from the center value, which differs from eye width. EQ has no direct equivalent, as it provides DC and AC gain. A minimum eye height is required for LOCK, and the 3 EQ ranges indicate valid eye height within the specified range. The objective was to determine AEQ MIN and AEQ MAX. If a minimum eye height is present at the deserializer receiver input, the DC and AC gain provide a more open eye, which must surpass the minimum eye height. There is no EOM for 94x. A possible CMLOUT RxEQ measurement previously existed.

    Aaron