TUSB321AI: NC Unused Pins

Matt Staniszewski

Part Number: TUSB321AI

Hi,

Below is the schematic of my TUSB321AI design. I wanted to have someone review it and also let me know if I can NC the VCONN_FAULT, ID and DIR pins when using the device in UFP mode?

Thanks!
Matt

over 6 years ago

0 Malik Barton57 over 6 years ago

TI__Guru 64326 points

Hi Matt,

VDD will need to be externally powered for this application as VBUs is not present until after CC role detection which cannot occur if TUSB321 is powered from VBus. VCONN_FAULT, ID and DIR pins can be NC.

0 Matt Staniszewski over 6 years ago in reply to Malik Barton57

Intellectual 360 points

Hi Malik,

Thanks for confirming the NC pins.

As for VBUS, this is on a UFP so VBUS is being input from a power source (i.e. AC adapter) so shouldn't it be available as soon as the port is connected? I was told this was OK in my post here: https://e2e.ti.com/support/interface/f/138/t/797707

Let me know.

Best,

Matt

0 Malik Barton57 over 6 years ago in reply to Matt Staniszewski

TI__Guru 64326 points

Hi Matt,

My apologies my earlier post was incorrect. TUSB321 will still present the Rd pull downs even when Vbus is not present in your schematic. This mean the role detection will happen and Vbus will be presented to the port. Sorry for the confusion. Your schematic otherwise looks good to go.

0 Matt Staniszewski over 6 years ago in reply to Malik Barton57

Intellectual 360 points

Thanks Malik, no worries, glad we are on the same page.

Cheers,
Matt

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TUSB321AI: NC Unused Pins