• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 877 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TUSB8041: TUSB8041 Schematic Review - Very simple implementation

Garrick88
Prodigy 140 points
Part Number: TUSB8041
Other Parts Discussed in Thread: TPD4EUSB30, TPD2EUSB30, TPD2EUSB30A

Hello,

We've put a very simple implementation of the TUSB8041 into our system; previously we had a TUSB4041, but ended up needing the connectivity to two USB 3.0 devices.

- No powered devices on USB; we put the voltage there, but have no plans to use it.

- Probably no configuration ever over I2C, but supported if needed

Anyway, I'd appreciate some quick feedback. Thank you!

  • 0
    TI__Expert 7395 points
    Hello Garrick,

    I have some observations on the schematic you attached:

    1- Remove R14 from USB_UP_P
    2- Remove the 15K pull-down resistors from the downstream ports (R18..R62)
    3- Use stronger PU/PD resistors on all configuration terminals; 4.7K recommended (i.e. OVERCURx, etc)
    4- The ESD protection diodes you selected (USBLC6) are designed for USB 2.0 ports. Those should be fine for the HS differential pairs (DP/DM), but those won't work for the SS differential pairs (Tx/Rx); I would recommend you to take a look at our TPD2EUSB30, TPD2EUSB30A, TPD4EUSB30 devices.
    5- Add 0.1uF coupling capacitors on the SS TX lines (Check figure 6 on the TUSB8041 datasheet, C7/C8)
    6- Make sure your power-up sequence complies with the requirements defined by the datasheet at section 7.6 .
    7- There is no need to populate some of the PU/PD resistors you added for device configuration:
    - R26, R27, R28 and R29. These are not needed since you are not implementing battery charging, overcurrent or power control on the downstream ports. So default configuration should be fine

    Regards,
    Jorge
  • 0 in reply to Jorge Llamas (SWAT)
    Prodigy 140 points
    Thank you. Excellent feedback.
  • 0 in reply to Jorge Llamas (SWAT)
    Prodigy 140 points

    Hi Jorge,

    I've attached an updated schematic here with your changes.

    In layout, I assume the coupling caps on the SS TX lines go as close to the USB connectors, as possible but just behind the DLP11SN900HL2L chokes and TPD2EUSB30A?

    Thanks, Garrick

    TUSB8041 ti.pdf

  • 0 in reply to Garrick88
    TI__Expert 7395 points
    Hello Garrick,

    Looks much better now. Just a couple of observations:

    1. Use stronger PU/PD resistors on all configuration terminals. I still see you are using 10K for R26, R27, R28 and R29. I would recommend to used 4.7K instead.

    2 Check frequency response for the common mode chokes you are using on the downstream ports at the SS differential pairs; I am not sure the selected model was designed to operate at SS.

    Regards,
    Jorge
  • 0 in reply to Jorge Llamas (SWAT)
    Prodigy 140 points

    Thanks. Updating resistors and chokes going to DLP11TB800UL2.