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TUSB211: USB Repeater for USB2.0 HS/FS/LS support in backplane based system

Sridevi K93
Prodigy 190 points
Part Number: TUSB211
Other Parts Discussed in Thread: TUSB212

Hi,

We have a 4-slot CPCI backplane. 

We have USB2.0 HS/FS/LS signals interfaced between the daughter cards via the backplane.

Please note that the system has to support live insertion of the daughter cards & the daughter cards should also have the required signal conditioning circuit as well.

As the trace length between the 2 slots is close to 18", we are planning to use TUSB211IRWBR as repeater in both the daughter cards. 

The overall end-to-end trace length of the signals can go upto 18" (considering the trace lengths within the daughter cards & the backplane)

Let me know if the TUSB211 part is fine to use for the backplane sort of application for signal conditioning & live insertion for USB2.0 interface.

Looking forward for your suggestion in this regard.

  • 0
    TI__Mastermind 36085 points

    Hello Sridevi,

        We have two options; the TUSB211 and the TUSB212, both devices detect when there is an HS connection and compensate its signal. This detection is constant, so the live insertion of the daughter cards is not an issue.

    The difference between both devices is that the TUSB211 only increases the slew-rate by injecting current to the HS signal. On the other hand, the TUSB212 enhances the slew-rate and also increases the eye amplitude by introducing a DC boost,   compensation capabilities.

    Please consider that the FS and LS signals are not affected by these devices.

    Regards,

    Diego.

  • 0 in reply to Diego Cortes
    Prodigy 190 points
    Hi Diego,
    Thank you for the reply.

    In our current design the MCU supports USB2.0 FS OTG port only in both the daughter cards. So please advice a suitable device then.

    Can you detail your comment which says:
    "Please consider that the FS and LS signals are not affected by these devices."
    Do you mean that TUSB211 is not suitable as repeater or signal conditioner for FS or LS? Please advice suitable part.

    Thank you.
  • 0 in reply to Sridevi K93
    TI__Mastermind 36085 points
    Sridevi,

    Unfortunately, we do not have such option for FS/LS. These connections run at a lower speed and its loss due to the channel is much lower compared with HS. I recommend to follow the layout recommendations below, so you can get the best performance in your design:

    www.usb.org/.../hs_usb_pdg_r1_0.pdf
    www.ti.com/.../scaa082a.pdf

    Regards,
    Diego.
  • 0 in reply to Diego Cortes
    Prodigy 190 points

    Hi Diego,

    Thank you for the detailed information & support.

    Pls correct me if am wrong - So I think if the PCB guidelines as per the shared document are adhered, USB trace length can even go upto 18" as well as shown in the image below. 

    Then even TUSB211 shall be removed as the overall trace length in our application through the backplane wil be <18". 

  • 0 in reply to Sridevi K93
    TI__Mastermind 36085 points

    Sridevi,

        That is correct, the TUSB211 shall be removed.

    Best regards,

    diego.