• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 1005 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.

DP83822H: SIGNAL INTEGRITY ISSUE

Brian Wang0928
Genius 14030 points
Part Number: DP83822H

Hello,

We found the signal integrity issue with DP83822H while doing normal operation test with 2pc motor drives. The bit error rate is over and up to 512 (Range: 0 - 512bits) after spin the motor for 3min. It looks the noise coming from the motor and affect the pcb routing of the DP83822H. Could you help to see layout if any improvements?  

Pease see the eye diagram and schematic here.

We tried to use external power supply to supply 5VD_PWR on control board, , the eye diagram can be improved.

Regards,

Brian

  • 0
    TI__Mastermind 23675 points
    Hi Brian,

    When running the motor can you try a few different configurations for me?
    1. Please put the PHY in reverse loopback to remove the MII from the equation (set register 0x16 to 0x0110).
    2. Please put the PHY in analog loopback to remove the MDI from the equation (set register 0x16 to 0x0108).

    While running both, please monitor for bit errors. Also, for analog loopback, please use a 100 ohm term cable.
    Here is an app note that will help explain both loopbacks:
    www.ti.com/.../snla266.pdf

    I'll review the layout.