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HD3SS3220: HD3SS3220 as a UFP interfaced to a Thunderbolt 3 DFP

Matt Krolick54
Intellectual 400 points
Part Number: HD3SS3220

I have a simple UFP system that I want to make sure works with a Thunderbolt 3 port (as on a laptop). I'd like to get 3A at 5V from it without negotiating USB-PD or entering Thunderbolt alt mode. Since the HD3SS3220 mux does not have USB-PD capability (thus Thunderbolt alt mode cannot be entered), I am relying on the CC1/CC2 pins to tell me the current capability (900mA, 1.5A, 3A). Is it the case that thunderbolt enabled devices always advertise a 3A capability (using the CC1/CC2 pins) before negotiating further using USB-PD?

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    TI__Expert 4325 points
    Hi Matt,
    A USB Type-C port has no requirement to advertise 3A. A device cannot assume a port can support 3A and/or USB-PD negotiation. The host can advertise any current level so your device must determine what's available and limit based on that. That said, if a Type-C port can source greater than 15W and supports USB-PD, it should advertise 3A on the CC pins.

    Regards,
    Brian