• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 33 subscribers
  • Views 201 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.

TUSB216: Please explain how signal conditioning occurs with shorted D1 and D2 pins

Michael Westberg
Prodigy 20 points
Part Number: TUSB216

Hi -

I see that there are many questions asked regarding TUSB216 and similar devices if D1 and D2 should/must be shorted under the device.

The only response I see is that yes, they should be shorted for correct function.

Please help me understand how this chip can signal condition the signals shorted? Please in technical detailed terms.

As the potential, boost and frequency must be identical if the two pads are shorted, what does the chip do? If we skip the chip and just have a trace it would have the same affect.

To me, it looks like saying that the below sample schematic would work exactly the same with or without the short over the diode.

This is very puzzling.

Thanks,

   Michael

  • 0
    TI__Mastermind 37330 points

    Hi Michael,

    The TUSB216 and in general the TUSB21X line of USB2.0 redrivers are able to boost USB 2.0 High-Speed signals coming from D1 and D2 by passively adding current to the signal as it passes under the redriver.

    The way this family of redrivers works is that instead of needing to be directly connected to the DP&DM1/2 lanes, the redriver can be placed directly over the trace of DP and DM at a point near the USB connector to have the USB signal passively boosted. Because of this, you can leave D1 and D2 shorted under the device, and it will still have its signal improved.

    Looking at the Layout example above, the DP/DM lanes stay shorted together as they go under the device, and will still be able to activate the redriver once a high-speed signal is detected.

    If you were to skip the device, the USB signal would not be boosted, resulting in a lower quality signal at longer lengths.

    If you have any other questions or concerns regarding any information with our USB2.0 Redrivers, please let me know!

    Thanks,

    Ryan