• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 33 subscribers
  • Views 375 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.

TUSB8044A: Maximum trace length without re driver

Abhishek singh
Expert 2000 points
Part Number: TUSB8044A
Other Parts Discussed in Thread: TUSB564

Hi  Team 

We are  using TUSB8044A in one of  our  device. It is connected to Nvidia  SoM as upstream port  and downstream port is connected to USB type C connector. 

Distance  between Nvidia SoM and  Usb hub is  40mm  and Hub to  type C connector as 100MM. Do you think  i should  use  USB driver bet USB hub and  Connector

if  i need  to support  1 Meter cable USB type C cable . 

How  i can practically  correlate insertion loss  parameter to trace length .    

  • 0
    TI__Guru 64326 points

    Hi,

    Your trace lengths are good and should not require the use of a redriver assuming layout is clean and does not add large stubs, etc. Remember that USB hubs "recreate" packets on the downstream port so loss form upstream connection is not seen downstream.

    To estimate insertion loss from trace length, it is best to look at the loss of you PCB material in dB/inch/GHz. then estimate the loss at the nyquist frequency of your expected signal. For FR4 this number is about  0.49 dB/inch at 2.5 GHz (USB 3 Gen 1). For Type-C you will also need to take into account the loss from your configuration mux at the type-C receptacle. 

    If yo are looking for a redriver/mux combo to consider for your design please look at TUSB542I or TUSB564 for DP Alternate mode applications (TUSB8044A is only USB 3 Gen 1 and does not handle DP data.) 

  • 0 in reply to Malik Barton57
    Expert 2000 points

    Hi  Malik 

    Thanks  for providing these  detail  it  helps a lot. In my  case Display port  will be  directly comes from Nvidia SoM . Now we are not planning to use Alt mode .

    Here  are  few  quick question  

    1)Do you  have any  idea  how  much loss i should  consider for cable to have a ball park idea. I do understand it  will  vary  from cable to cable .

    2) Does TI have any USB hub which can offer  10Gbps in downstream part @-40 to +85 degree centigrade.

  • 0 in reply to Abhishek singh
    TI__Guru 64326 points

    Hi Abhishek,

    1) You can assume 7dB loss for a two meter Type-C cable. This is referenced from the USB 3.1 loss budget document found on usb.org.

    2) We only have USB 3 Gen 1 hubs available, TUSB80xx line of hubs. 

  • 0 in reply to Malik Barton57
    Expert 2000 points

    Hi Malik  

    Thanks for providing these  details.