TUSB1210: Unused VBUS

Nicole Wreyford

Prodigy 101 points

Part Number: TUSB1210

Tool/software:

Good day,

Can the TUSB1210 device be used in Host mode with the VBUS pin not connected?

We will not be using the VBUS detect or CPEN.

Should I leave the VBUS pin not connected, GND or just connect it to 5V and add a decoupling capacitor?

If I want to use it in Device mode, can I still have this connected to 5V and a decoupling capacitor?

10 months ago

0 Vishesh Pithadiya 10 months ago

TI__Mastermind 44971 points

Hi Nicole,

Vbus needs to be provided by the USB host for the cable detection functionality of USB2. You should not be able to communicate data without supplying this.

0 Nicole Wreyford 10 months ago in reply to Vishesh Pithadiya

Prodigy 101 points

Hi Vishesh,

The one USB2 on my board comes from an internal microcontroller. Will I still need to connect 5V at VBUS?

0 Vishesh Pithadiya 10 months ago in reply to Nicole Wreyford

TI__Mastermind 44971 points

Hi Nicole,

Some Devices will have terminations on the D+ and D- regardless of the status of Vbus, and other devices will require that Vbus is present before the terminations are set. To keep your design robust its best to attach 5V and add a decoupling cap to ground, as some devices will need to see the 5V on Vbus.

0 Nicole Wreyford 10 months ago in reply to Vishesh Pithadiya

Prodigy 101 points

Hi Vishesh,

The device on the other end does not have a VBUS connection to the PHY. We have separate circuitry in a different part of the design that controls a 5V output to the USB connector (for specific standard compliance). Will the TUSB1210 PHY work without the 5V for both host and device, or only if in host mode?

The datasheet, p54, states the following:

+1 Brian Zhou 10 months ago in reply to Nicole Wreyford

TI__Guru**** 151105 points

Hi Nicole:

for host, TUSB1210 VBUS pin can be floating or grounded. As device, TUSB VBUS pin is used as VBus detect and needs to be connected to USB connector or 5v.

so for OTG, VBUS pin need to be connected to USB connector or 5V.

Best

Brian

0 Nicole Wreyford 10 months ago in reply to Brian Zhou

Prodigy 101 points

Thank you Brian. I will connect it to 5V just to be safe. This will still be fine for the host, correct?

+1 Vishesh Pithadiya 10 months ago in reply to Nicole Wreyford

TI__Mastermind 44971 points

Hi Nicole,

Yes, this should be fine.

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TUSB1210: Unused VBUS