• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 33 subscribers
  • Views 547 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.

[ TUSB211 ] Signal after continuous identical bit cross the center of eye

Kenichiro
Mastermind 9165 points
Other Parts Discussed in Thread: TUSB211

[ TUSB211 ] Signal after continuous identical bit cross the center of eye

Hi, Expert,

My customer has found that the signal transition just after few continuous identical bit (ex. 00001, 11110) cross the center of eye as drawn below.



Here, what I checked with customer.

  • During eye measurement, ENA_HS pin output high.
  • Customer does not use USB TEST_PACKET, because at this moment, this is not the experiment for USB compliance test.
  • Different EQ setting does not show much different result.

I'm sorry that I'm not allowed to post their waveforms on public space.
If you can send private message to me, I can share more result with you.

tanaka-k(at)clv.macnica.co.jp

Thank you for your support in advance.

Thanks,
Ken

Other Reference Discussion
TUSB211 - not activating
e2e.ti.com/.../469595



  • 0
    TI__Mastermind 36085 points
    Hello Kenichiro-san,

    Please send me the test results to diego.cortes@ti.com, as a first approach I think that the customer is experiencing high DC loss, our device does not compensate this kind of degradation, only improves the slew rate, that's why the issue seems to be happening on the non transition bits. In the meantime they can try to increase the drive strength on the PC PHY or try with a second EVM close to the PC (so one would be close to the device and the other close to the PC). Also please let me know the trace length on the device's board and the length of both USB cables.

    Regards,
    Diego.