• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 33 subscribers
  • Views 221 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.

DP83822I: Difficult for him to route with 50-Ω impedance to ground between transformer and RJ45 connector

Motoyasu Hattori
Genius 10955 points
Part Number: DP83822I

Hi,

My customer has questions of connection between RJ45 connector and transformer with DP83822.  We can find MDI Layout Guideline on the datasheet P.105.   Does this guideline apply the line between transformer and RJ45 connector?

He can route trace with 100-Ω differential controlled impedance, however, it is difficult for him to route with 50-Ω impedance to ground, ie. It is difficult to put GND layer below MDI signal layer (top layer), but signal is very short.   Does TI recommend to route with 50-Ω impedance to ground?   Also, if it is difficult to route with 50-Ω impedance to ground, on the case of very short trace, do you have any idea?   Please advise us.

Thanks and best regards,
M.HATTORI.

  • +1
    TI__Mastermind 39785 points

    Hi Hattori-san,

    The 50 ohm to GND impedance routing after the transformer is less critical than the 100 ohm differential. While not ideal, it is important to keep the 100ohm differential controlled impedance requirement satisfied at all times.

    Sincerely,

    Gerome