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TUSB8041: deviation of transmission ability

Shinichi Inoue
Guru 21696 points
Part Number: TUSB8041

Dear Specialists,

My customer is considering TUSB8041I and has a question.

I would be grateful if you could advise.

---

Regarding TUSB8041I,

How is the difference of transmission ability each device.

I am thinking of using multiple devices to perform transmission of USB 3.0 full bandwidth.

I am concerned about how the individual difference in performance will affect the system.

Exact values ​​are not necessary, it is enough to know the order.

(For example, Individual differences should be less than 0.3% when excluding clock variations, etc.)

Also, is there a relatively large variation factor besides external clock?

I think that the accuracy of the external clock is major factor of performance change, I' like to know the other.

---

I appreciate your great help in advance.

Best regards,

Shinichi

  • 0
    TI__Guru 60870 points
    Hello Shinichi,

    USB is a master-slave bus, so the host controller handles the scheduling of all transactions. If one device connected to the hub is slow, the host will access another device. The TUSB8041 does not schedule any data transfers, but it does allow for some packet buffering which results in improved throughput.

    Regards,
    JMMN
  • 0 in reply to JMMN
    Guru 21696 points

    Hi JMMN,

    Thank you for your reply.

    The customer simply would like to know

    ---

    (1) the dispersion of the transmission distances of the device if other conditions are the same.

    (2)What is the factor that affects the transmission performance next to the clock? How much is it affected?

    ---

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Guru 60870 points
    Hello Shinichi,

    For USB signal quality, PCB routing (impedance matching, length matching, etc) and the choice of good quality connectors have the largest impact. There are layout recommendations in the datasheets of all TI USB products.

    Regards,
    JMMN
  • 0 in reply to JMMN
    Guru 21696 points
    HI JMMN,

    Thank you for your reply.

    I would be grateful if you could advise question (1).

    (1) the dispersion of the transmission distances of the device if other conditions are the same.

    The customer'd like to know that ,TUSB8041I only, the difference of transmission distance between best and worst case.

    Do you have any suggestion?

    I appreciate your great help.

    Best regards,
    Shinichi
  • 0 in reply to Shinichi Inoue
    TI__Guru 60870 points
    Shinichi,

    We can not quantify transmission difference between best and worst case based on the TUSB8041 alone, it will depend on cable quality, board routing, etc.

    Regards,
    JMMN
  • 0 in reply to JMMN
    Guru 21696 points

    Hi JMMN,

    Thank you for your reply.

    I understand it is not available only TUSB8041.

    I'll send this information to the customer and make him understand.

    I appreciate your great help.

    Best regards,

    Shinichi