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TUSB320LAI: Question about the connection of VBUS_DET terminal.

Kazuya Nakai59
Guru 21705 points
Part Number: TUSB320LAI
Other Parts Discussed in Thread: TUSB320

Hello guys,

One of my customers considering using TUSB320LAI for their new products.

At this moment, they have the following question.
Could you please give me your reply?

Q. We are considering using TUSB320LAI for DFP side port of USB type-C.
     We don't need to implement PD function.
     In this case, should VBUS_DET be open or be connected to VBUS line via 900kohm resistor like Figure 16 of the device datasheet?       

Your reply would be much appreciated.

Best regards,
Kazuya.

  • 0
    TI__Guru*** 148155 points

    Hello:

     For DFP,  VBUS_DET can be connected to VBUS line via 900kohm resistor like Figure 16 of the device datasheet.

    Best

    Brian

  • 0 in reply to Brian Zhou
    Guru 21705 points

    Hello Brian,

    Thank you very much for our reply and I'm sorry to be my late response due to summer vacation.

    Could I confirm you your reply about VBUS_DET?
    TUSB320LAI datasheet says that "The TUSB320 device supports VBUS detection according to the Type-C specification. VBUS detection is used to determine the attachment and detachment of a UFP and to determine the entering and exiting of accessary modes. VBUS detection is also used to successfully resolve the role in DRP mode. The system VBUS voltage must be routed through a 900-kΩ resistor to the VBUS_DET pin on the TUSB320 device if the PORT pin is configured as a DRP or a UFP. If the TUSB320 device is configured as a DFP and only ever used in DFP mode, the VBUS_DET pin can be left unconnected."
    at 7.2.5 VBUS Detection section on page 12.

    The customer wants to use TUSB320LAI as DFP side port without PD function.

    Which is better connection of BUS_DET for their usage, VBUS_DET must be left unconnected or must be connected to VBUS line via 900kohm?

    Could you give me your reply for double checking?

    Thank you again and best regards,
    Kazuya.

  • 0 in reply to Kazuya Nakai59
    TI__Guru*** 148155 points

    Kazuya:

       For DFP, VBUS_det is not used. it can be either floating or connected with 900k to Vbus.

    normally we still connected Vbus_det with 900k to Vbus.

    Best

    Brian