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DS90UB954-Q1: ds90ub960/ds90ub964 layout problem

Qianqian
Genius 5010 points
Part Number: DS90UB954-Q1

Dear TI Experts,

I am now using ds90ub960/ds90ub964/ds90ub954,and have some layout problem needs your suggestion:

DS90UB954:

  1：I have read the Layout Guide,and don’t find the description of  layout line impedance between 954 and AC coupling capacitors, must it to be 100Ω  impedance？

  2：Must the bottom reference layer of AC coupling capacitors be  hollowed ? DS90UB954 EVM does the hollowing，but I cann't find the description in the Layout Guide

        By the way,   It's found in the layout guide that the reference layer of the magnetic bead connected to RIN+ need to be hollowed out, but DS90UB954 EVM didn't do the hollowing

 

DS90UB964:

Their is not much layout guide in the 964 datasheet besides a picture, what's the best way to do this?

DS90UB960:

 AC coupling capacitors hollowing；three magnetic beads hollowing。

And the two GND,GND2 is layer4,between these their is a signal layer

960/954/964 layout guide are different from EVN,I'd like to confirm which should I refer to?Cause I am now optimizing the layout.

You can refer to the layout picture in the document.Hoping for your reply,Thank you very much~Layout.zip

  • 0
    TI__Mastermind 30515 points
    All the layouts are similar, the high speed layout can be helpful for all FPD-Link parts, the key rules:
    1. impedance matching and continuous: the diff. pins should be diff. 100ohms, and single-end 50ohms impedance.
    2. the hollowing under the AC coupling is for better control the trace impedance, this is one impedance control skill, NOT must be mentioned in user guide if you can have better impedance control skills in the ac coupling position.
    3. the hollowing under the inductor is for better noise control, this is better in some cases.

    best regards,
    Steven