What is the function of VDD_USB_CAP

[carolyn_zhang]

Hi,

It looks like the USB of i.MX RT can be used normally no matter VDD_USB_CAP is floated or not. I just wander what is the function of VDD_USB_CAP. Thanks.

[victorjimenez]

Hello Carolyn, 

VDD_USB_CAP is the output of the USB_LDO regulator. It's not recommended to leave this pin floating, please refer to the below suggestion: 

In the case of all our evaluation boards, we use these two capacitors 0.1uF and 10uF. Having these two capacitors help to have a more stable USB voltage. 

Have a great day,

Victor

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[giuseppescarpi]

Hi @victorjimenez,

I'd like to follow-up this question.

The board I'm working has very limited room available. I plan NOT to use USB, so the question is: can I leave VDD_USB_CAP floating?

Thanks

Giuseppe

[carolyn_zhang]

Hi, Victor,

Thanks.