BF707 USB0_VBUS and ADUM4160


I'm working on a design using the usb0 port from the ADSP-BF707 and the isolator ADUM4160. The USB will ever be in peripheral mode. I found some guidelines how to connect the USB0_ID and USB0_VBUS pins in peripheral mode but no information about the USB0_VBUS pin. In the datasheet of the ADUM4160 in Figure 4 is a typical application as peripheral shown where VDD2 and VBUS2 is connected to 3.3V. In my design I connect it  the same way.

My question is:

How do I have to connect the USB0_VBUS pin at the BF707 in peripheral mode? Can I left the pin open or connect it to ground or do I have to connect the USB0_VBUS pin also to 3.3V for correct operation. The VDD_USB voltage is 3.3V. 

Thanks for helping.