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TUSB211 - not activating

nemesys
Prodigy 90 points
Other Parts Discussed in Thread: TUSB211, USB-REDRIVER-EVM

Hi,

I developped a small board which interface a TUSB211, two USB connectors and a voltage regulator to convert one side's VBUS to the TUSB211 necessary 3V3 power supply (see attached schematic).

I'm doing some eye diagrams with an appropriate Agilent scope and a host generating test packets.

The TUSB211 has no effect; I compared with a board without the TUSB211 and it does not change a thing.

I also tried with various value of EQ resistor, still no effect.

ENA_HS and CD are always at 0V, so is VREG.

Toggling the RST pin also has no effect.

Any help would me very appreciated.

  • 0
    TI__Mastermind 36085 points

    Hello,

        Please confirm the following two aspects:

        1) Input and output must be shorted (DP DP_B with DP_A and DM_B with DM_A).

        2) The TUSB211 compensates HS only, the LS & FS signals are bypassed.

    Regards,

    Diego.

  • 0 in reply to Diego Cortes
    Prodigy 90 points

    Hi Diego,

    1) Yes, both input and output are shorted as requested in the datasheet

    Edit : I rechecked the ENA_HS and CD signals, they are both high.

    I attached the scope report, I did the test with various boards with different values of EQ resistor and as you can see, the eye does not change a lot (which is probably due to the board difference themselves).

    Regards

    TUSB211 tests.zip

  • 0 in reply to nemesys
    Prodigy 90 points

    Edit : I was not having ENA_HS high like I previously mentionned.

    The problem was that the TUSB211 power supply came at the same moment as the USB test packets. 

    Like mentionned in the datasheet, the TUSB211 requires to be power supplied in the full USB path before the test packets can be sent otherwise it will not function properly.

  • 0 in reply to nemesys
    Prodigy 10 points
    We recently purchase the USB 2.0 and USB 3.0 Re-driver Evaluation Module ( USB-REDRIVER-EVM ), www.ti.com/.../usb-redriver-evm, the TUSB211 is not active also.
    1. Checked the power supplied to be 3.3V, which is good.
    2. Then replace the TUSB211 twice, and change the EQ setting from 1.6k to 3.9k, but still not able to get it to work.
    3. We also tested on ENA for insertion loss, by itself the module has about 10 db drop due to not active TUSB211 and connector loss

    all the test is done after TUSB211 is power supplied.

    Any other suggestion?
  • 0 in reply to Fuwen Xu
    TI__Expert 3625 points

    As per datasheet this exact sequence needs to be followed.

    If 4 happens before 3, the amplitude will be incorrect (too high) and it will not be a valid USB HS signal and TUSB211 will not activate since it is not a valid USB HS signal. 3 needs to happen so that 45 ohm termination exists and the signal level will be correct and TUSB211 will activate.

  • 0
    TI__Expert 3625 points

    Another comment on the layout .the TUSB211 device could be rotated 180degree so the DP/DM swapping on the layout is not needed