DRV8301: Are PVDD1 and PVDD2 power supplies completely independent?

Part Number: DRV8301

Hello,

Is it possible to supply PVDD1 and PVDD2 by two different sources? 

For example if PVDD1 is no longer supplied but PVDD2 is connected to 12V, does buck converter still work (does it generate 5V) ?

Morever if using an external DC/DC converter instead of this internal buck converter, can we remove all peripheral components related to RT_CLK, VSENSE, SSTR, COMP, and remove power source from PVDD2 pins? Should we leave these pins free (except EN_BUCK pin, must be connected to GND)?

Thank you for your support.

Best regards,

Samy