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TUSB321AI: Processing unused pins.

Kengo.Y
Guru 11245 points
Part Number: TUSB321AI

Hi team.

I'd like to know about processing unused pins.

My customer want to detect only the front and back of Type-C.
So, could you tell me how to handle these pins?
 VBUS_DET
 VCONN_FAULT
 OUT1/2
 ID

Sincerely.
Kengo.

  • 0
    TI__Guru 64326 points

    Hi Kengo,

    If unused these pins can be left unconnected. However if TUSB321AI is used on UFP (or DRP as sink) mode VBUS_DET should be connected to Vbus from the Type-C connector. In  DFP (or DRP as source) mode, ID pin should be used to open and close the Vbus switch. 

  • 0 in reply to Malik Barton57
    Guru 11245 points

    Hi Malik,

    Thank you for your reply.
    And I'm sorry for the delayed reply.

    What happens when the connection destination is the same TUSB321AI and in DRP mode(pin is float)?

    Or, If Sink and Source are determined by the customer's app, have them set to DFP or UFP.
    What is your recommend resistance value of the pull-up for UFP?

    Sincerely.
    Kengo.

  • 0 in reply to Kengo.Y
    TI__Guru 64326 points

    Hi Kengo,

    If TUSB321AI in DRP mode is connected to another DRP then a race condition occurs to see which port presents a Rp first while the other presents a Rd. To have some more control over this scenario Try.SNK and Try.SRC can be implemented. These methods change the CC negotiation timing such that a DRP port that implements Try.SRC will become a DFP (DRP acting as host) or a DRP port that implements Try.SNK will become a UFP (DRP acting as sink).

    If using TUSB321AI as a UFP, PORT should be pulled down to GND by a 4.7k resistor.