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TUSB320LAI: Datasheet clarification for UFP application

Martin Monroy
Prodigy 20 points
Part Number: TUSB320LAI
Other Parts Discussed in Thread: TUSB320

Tool/software:

Hello,

I am currently working on a battery powered product design which features a USB-C UFP. This port is to be handled by the TUSB320LAI, so as to determine the current capability of a plugged source in order to configure a battery charger's C-rate.

Our USB interface supply is currently 3.3V, regulated from Vbus. Hence the TUSB320LAI's Vdd is 3.3V, with startup upon insertion of the source. 

I would need clarification on the following statement from the datasheet : 

" If a DFP advertises 3 A, system designer must ensure that the VDD of the TUSB320 device is 3.5 V or greater." (§7.2.2 Type-C current mode)

Does this apply only to applications where the TUSB320LAI is embedded in a DFP ? Or does it apply to UFP being presented such 3A-capable DFPs ? I would like to assess whether our UFP with Vdd = 3.3V is going to function properly with a 3A DFP, which will be our main use case.

Best regards,

Martin

  • 0
    TI__Mastermind 37330 points

    Hi Martin,

    If the advertised current from the DFP is 3A, yes, the TUSB320 needs to have a VDD of 3.5V or greater. Otherwise, it cannot support a 5V/3A application.

    Thanks,

    Ryan

  • 0 in reply to Ryan Kitto
    Prodigy 20 points

    Hello Ryan,

    When you talk about "the DFP" do you mean the charger which I am plugging into the device which features the TUSB320 (which is then UFP) ?

    In the meantime I have found this other thread about the same issue, where it seems that this recommendation only applies if I am configuring the TUSB320 as a DFP, which is not my case here.

    Best regards,

    Martin

  • 0 in reply to Martin Monroy
    TI__Mastermind 37330 points

    Hi Martin,

    I double checked internally, and actually you do not have to use >3.5V for the UFP. You can use 3.3V for a UFP application regardless of the advertised current. The >3.5V VDD requirement for DFP is only to help provide the required current needed for 5V/3A advertisement. 

    Thanks,

    Ryan