TUSB8020B: Can be connected USB_VBUS to VDD directly?

user6390769

Prodigy 80 points

Part Number: TUSB8020B

HI E2E

Can we connect the VBUS terminal directly to the VDD?　Is there any problem?

Regards,

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 317250 points

No. The absolute maximum rating is 1.4 V.

The 1.1 V and 3.3 V power rails must be provided by your board.

0 JMMN over 3 years ago in reply to Clemens Ladisch

TI__Guru 60870 points

Yes, you will need separate power rails, you can use the EVM as a reference design: https://www.ti.com/tool/TUSB8020BEVM

Regards,

JMMN

0 user6390769 over 3 years ago in reply to JMMN

Prodigy 80 points

Thanks for your comments.

Sorry for not explaining enough, "USB_VBUS" terminal(9th pin of TUSB8020B) can be connected to VDD(1.1V voltage) directly?

VBUS signal from USB type-B connector is voltage-converted to 3.3V, and input to our custom ASIC, it's USB DM/DP pair is connected to TUSB8020B downstream1 port(USB_DP_DN1, USB_DM_DN1).

Regards,

0 JMMN over 3 years ago in reply to user6390769

TI__Guru 60870 points

USB_VBUS is a detection input to the hub, so it should be driven by a signal that will only be high when an active host is connected to the upstream port of the hub. If you use a 3.3V or 1.1V signal to drive the USB_VBUS input, the resistor divider values can be changed so that the USB_VBUS = 500 mV when high.

Regards,

JMMN

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TUSB8020B: Can be connected USB_VBUS to VDD directly?