TUSB1044: Asking for TUSB1044 Aux connection in USB mode

SHH

Mastermind 32146 points

Part Number: TUSB1044

Hi Team,

customer uses TUSB1044 in USB mode only.

Can the Aux pins be floating?

BR,

SHH

over 4 years ago

+1 David (ASIC) Liu over 4 years ago

TI__Guru**** 176741 points

SHH

Customer can leave SBU1/2 pins floating. Suggest pulling up AUXN to VCC with 1M ohm and pulling down AUXP to GND with 1M.

Thanks

David

0 SHH over 4 years ago in reply to David (ASIC) Liu

TI__Mastermind 32146 points

Hi David,

Would you please review customer's question here? Thanks for help!

From the DisplayPort standard specification, the upstream DP device is to pull-down AUX+ line and pull-up AUX- line with 10K~105K ; and downstream devices is to pull-up AUX+ line and pull-down AUX- line with 1Mohm.

Please advise why your suggestion is different from the standard above.

And from the TI forum(see link below), the suggestion is to let SBU/AUX pins floating if doesn’t use the DP alt mode, could you double check it, thanks

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/899963/tusb544-sbu-and-aux-not-used

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/916936/tusb1044-operation-of-tusb1044-at-usb-mode-only