Solved: If 3.3V is applied to D+ (or D-) without supplying... - Infineon Developer Community

10 likes received

100 sign-ins

50 questions asked

Hello,

If 3.3V is applied to D+ (or D-) without supplying power to VCC (VCC_D/VCC_A), will the device be damaged?

Please tell me about the downstream and upstream ports respectively.

Regards,

Shimamura

Subscribe

1 Solution

250 solutions authored

500 replies posted

250 replies posted

Hi Shimamura,

As you might be knowing, D+ is pulled up to 3.3V. As per USB spec, the voltage source on the pull-up resistor must be derived from or controlled by the power supplied on the USB cable such that when VBUS is removed, the pull-up resistor does not supply current on the data line to which it is attached. So, in absence of VBUS 9VCC), there shouldn't be current on the data lines.

Regards,

Mallika

View solution in original post

1 Reply

250 solutions authored

500 replies posted

250 replies posted

Hi Shimamura,

As you might be knowing, D+ is pulled up to 3.3V. As per USB spec, the voltage source on the pull-up resistor must be derived from or controlled by the power supplied on the USB cable such that when VBUS is removed, the pull-up resistor does not supply current on the data line to which it is attached. So, in absence of VBUS 9VCC), there shouldn't be current on the data lines.

Regards,

Mallika