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TUSB211-Q1: TUSB211QRWBRQ1 Eye pattern issue

Chris Park
Prodigy 305 points
Part Number: TUSB211-Q1
Other Parts Discussed in Thread: TUSB211

Dear all,

 

This is Chris Park from TI Korea and I support Automotive mass market. One of my key customers has asked several questions regarding the eye pattern of usb conditioner TUSB211QRWBRQ1.

 Below is the block diagram of the conditioner and eye pattern. Please refer to the schematic and the details. EQ0=100,EQ1=1800,EQ2=3900,EQ3=9100 ohm.

 

The questions are as follow;

  1. As you could see from below picture, the eye pattern doesn't change according to the EQ resistance. Does the eye pattern change when the customer changes EQ resistance?
  2. The customer noticed that there is no change in eye pattern even when the power (VCC) is not put to the conditioner. Why does it look like it’s working even without the power supply?
  3. Is there any guide to the values of inductor and resistor at D1P / D1M? Could they be 0ohm?

 

 

Thank you.

  • 0
    TI__Guru 60865 points

    Hi Chris,

    Answers in line below.

    1. As you could see from below picture, the eye pattern doesn't change according to the EQ resistance. Does the eye pattern change when the customer changes EQ resistance?

    [JN] The TUSB211 will only apply a change in the EQ resistance after a reset or power cycle, it cannot be changed real time.  Please confirm that the redriver is active by checking the ENA_HS output.  Please note that the TUSB211 will impact the left side opening of the eye diagram, you should not expect to see the DC levels move. 

    1. The customer noticed that there is no change in eye pattern even when the power (VCC) is not put to the conditioner. Why does it look like it’s working even without the power supply?

    [JN]  Please confirm that the redriver is active by checking the ENA_HS output.  Can they check for power leakage to the redriver that is powering it?

    1. Is there any guide to the values of inductor and resistor at D1P / D1M? Could they be 0ohm?

    [JN] We don't have any recommendation on inductors / resistors at the D1P/D1M. 

    Regards,

    JMMN