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TUSB8041: TUSB8041 Input Supply Current

Jeremy Novoa
Prodigy 130 points
Part Number: TUSB8041

I am trying to calculate the require power for this 12 port hub. In the TUSB8041 data sheet section 7.7 there is some parameter so with that information I am trying to estimate base on my configuration and connected devices.

All my connected devices will be USB2.0 and according to the datasheet if my host is USB2.0 and my connected devices are USB2.0 the current drawn from the TUSB8041 is 3.3V @ 76mA and 1.1V @ 86mA. What I don't know (not on the data sheet) is what happens when you cascade the TUSB8041.

For example, if my host supports USB3.0 and USB2.0 and I have two TUSB8041 cascaded and all my connected devices are USB2.0, is it true that the two TUSB8041 will be working in "USB2.0 mode"? If true, is the current drawn for each TUSB8041 will be 3.3V @ 76mA and 1.1V @ 86mA plus the current drawn by the connected devices?

Thank you,

Jeremy

  • 0
    TI__Expert 7395 points
    Hello Jeremy,

    If you are connecting a TUSB8041 to a downstream port, connection at that port will be performed at both SS and HS, since the TUSB8041 is SS capable.
    If you are intending to connect only USB 2.0 devices, you can leave the SS differential pairs (TX/RX) floating, or even better, use a HS hub, like our TUSB4041

    Please also note that the typical current consumption defined on the datasheet for "2.0 host / 4 HS Devices" is observed only after the device has been properly configured (i.e. default configuration values loaded after reset is asserted). However, during a brief period of time, while the device is un-configured, it can consume much higher power (same as defined at the "SMBUS Programming current" field)

    Regards,
    Jorge