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TUSB321 - Recommended schematic for UFP application

Guru 19785 points
Other Parts Discussed in Thread: TUSB321, HD3SS2522, HD3SS3212

Hello Team,

There is an typical application schematic for DFP application. How about for UFP application ?

I also found that the datasheet does not have pull up resistors on CC1, CC2 lines. I believe the resistors are required externally. Customer may misunderstand that TUSB321 may include pull up resistors.

Best Regards,

Kawai

  • Hello Kawai-san,

        

        You don't need the pull-up resistors on the CC pins, and the schematic for UFP implementation it's pretty much the same as the DFP, the only difference is to connect the port pin to GND, that's it.

    Regards,

    Diego.

  • Hello Diego-san,

    Sorry that I am not much familiar to USB type C application.

    I was understanding that type C device recognizes the CC detection by the pull up resistor at DFP and pull down resistor at UFP side. However, TUSB321 could be set to DFP/UFP by setting the PORT pin, is that the reason why you would not need resistors ?

    Another question for HD3SS2522. For this device, you would need pull up resistors on CC pins, am I correct ?

    Best Regards,
    Kawai
  • Hi Kawai-san,

    You are right, the TUSB321 handles thePull-up/down resistors by means of the PORT pin configuration and you don't need to include them externally. Meanwhile the HD3SS2522 needs the external pull ups resistors, please refer to the EVM users manual , where you will find an example of RP resistors for each current advertisement (www.ti.com/.../sllu215a.pdf, bottom center page 9).

    Regards,
    Diego.
  • Hello Diego-san,

    Thank you for your continuous support and the above information.

    Best Regards,
    Kawai
  • Hello,

    I'm using TUSB321 + HD3SS3212 for type-C application and want to set the configuration for DRP to support both DFP and UFP.
    Is there any reference schematic? I'm not sure where to connect for out1 and out2 of TUSB321. Any suggestion or use case?
  • Hello,

        You can follow the figure 4 from the TUSB321 datasheet (but leave the PORT pin as not connected) as reference. OUT1 and OUT2 are open drain outputs, so they need a pull-up resistor to work properly (4.7kOhms is OK for the application), use these outputs to notify the detected current mode and prevent an over current event.

    Regards,

    Diego.