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TUSB8020B: TUSB8020B Default Code and Current Constumption

Part Number: TUSB8020B

Hi there,

I have some questions about the TUSB8020B;

1. The EVM board uses a 1.5A capable Voltage Regulator for 1.1V, why is this? 

2. If the chip is a 3.0 Host Device with a 3.0 device connected on port 1 and a 2.0 device connected on port 2, what would be the likely current draw of the chip?

3. Can the TUSB8020B work right out of the box, no programming required? 

Many Thanks, 


  • Hi Callum,

    1.  TUSB8020B EVM design reused the power scheme from the higher power 4 port hub.


    3.  Correct, the hub is a hardcoded state machine based design that does not require programming.  Make sure that SMBUSz is not pulled low and a blank EEPROM is not attached or the hub will enter configuration / programming mode.



  • Thank you for the reply JMMN,

    For question number 2, does that mean TUSB8020B will draw that current from the USB host device? The USB 3.0 Device that I will have connected could draw up to 600mA

  • Hi Callum,

    The TUSB8020B is not a USB compliant bus-powered hub (its descriptors report as self powered and its suspend power consumption is too high to qualify).  However, functionally, the hub does not check where it is powered from and it can be bus-powered if there enough current supplied from the USB host.  The power listed in the datasheet is for the hub only, and does not include any downstream devices.