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TUSB2E11: About the power consumption when the system enters the Modern Standby

KAITING Tu
Prodigy 20 points
Part Number: TUSB2E11

Tool/software:

Hi,

We are evaluating how much additional power consumption might be incurred by using an eUSB2 repeater when the system enters the Modern Standby. (The eUSB2 state should be L1 or L2.) I saw related information in the datasheet. But I am not sure whether this value includes the contribution of the pull-up and pull-down resistors on the eUSB2 bus. Could you kindly confirm this for us? Thanks!!

For example,

The presence of both pull-up and pull-down resistor on the USB D+ line result in additional power consumption.

  • 0
    TI__Mastermind 38925 points

    Hello,

    The power consumption values in the datasheet do not include any pull-up or pull-downs on the data lines. These are values taken purely from the devices operation.

    Please let me know if you have any other questions.

    Thanks,

    Ryan

  • 0 in reply to Ryan Kitto
    Prodigy 20 points

    Hi Ryan,

    Thank you for your reply.

    1. If the USB2.0 device runs in full speed mode,does the eUSB bus need to be pulled up? (eD+ or eD- or Both?)
    2. According to your experience, may I know the expected increase in power consumption (including the contribution of the pull-up and pull-down resistors on the eUSB2 bus) using an eUSB2 repeater when the system enters the Modern Standby?
  • 0 in reply to KAITING Tu
    TI__Mastermind 38925 points

    Hi Kaitang,

    From my experience, the USB bus lanes should not need to be externally pulled up by anything. Anything like that would be handled internally by the TUSB2E11.

    We do not have any experience with externally pulling these lines up, as this is not something we test or characterize. Our EVM is a good example of what we would expect a typical eUSB2 bus to look like, where the only "pull-down" present are termination for the bus for internal testing. These are not pull-downs you should need in your connection:

    Thanks,

    Ryan

  • 0 in reply to Ryan Kitto
    Prodigy 20 points

    Hi Ryan,

    Sorry for the confusion. I may not have explained clearly.

    1. If the eUSB2 device runs in full speed mode, does the eUSB2 bus require the internal pull-up resistor? (eD+ or eD- or Both?)
    2. According to your experience, may I know the expected increase in power consumption (including the contribution of the pull-up and pull-down resistors on the eUSB2 bus) using an eUSB2 repeater when the system enters the Modern Standby?

     

  • 0 in reply to KAITING Tu
    TI__Mastermind 38925 points

    Hi Kaiting,

    Okay, I understand now I think. Let me ask some other engineers in the background just to make sure, and I will try to get you an answer by the EOD Monday, 6/30.

    Thanks,

    Ryan

  • 0 in reply to Ryan Kitto
    Prodigy 20 points

    Hi Ryan,

    Just wondering if there might be any updates you could share? Thanks

    KAITING

  • +1 in reply to KAITING Tu
    TI__Mastermind 40190 points

    Hi,

    KAITING Tu said:
    If the eUSB2 device runs in full speed mode, does the eUSB2 bus require the internal pull-up resistor? (eD+ or eD- or Both?)

    This depends on the speed of operation. in HS mode, no PUP and PDOWN will be present, in LS we will see the PUP on eD+, and in FS we will se ethe PUP on eD-.

    KAITING Tu said:
    According to your experience, may I know the expected increase in power consumption (including the contribution of the pull-up and pull-down resistors on the eUSB2 bus) using an eUSB2 repeater when the system enters the Modern Standby?

    The measured power consumption in the low power states includes the PUP and PDOWN present in the eD+ eD- path. Its difficult to isolate the exact power consumption of this resistor divider in the silicon itself. 

    When in idle mode the TUSB2E11 will pull no more than 5mW in any low power state. Where L1 is the highest power draw.