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Hi,
from ds , USB current /MHz :
-> so at 200M could be around 0.6 mA .
and VDDusb has to be: (same as VDD , if used )
>VDDUSB should be 3.3V. Is this correct?
Right, as usb is working on 3v3 signal level, the transceiver obviously has to work at 3v3 ,
otherwise it could not send anything at usb standard signal level. (full or high speed)
+
Why you want to know at uA precision, how much current is needed ?
Anyway this is a burst/pulse packet communication, so - as @FBL said - it depends a lot on actual use case;
from "sleep" = active, but doing nothing, to transmitting at max speed , is a big range.
So just lets look at H743 ds, where (average ! , not peak) current is given:
in uA/MHz run mode; so at 200MHz about (30*200) 6000uA, 6mA . (all at 3v3 VDD , at 25°)
BUT biggest part here, registers and kernel, are probably in the H563 at MCU voltage, so the main consumption is on the 1v8 core supply, only a part at the 3v3 .
At high temp the current is higher...so if you want to know exactly : use a H563 nucleo board, set core VDD_MCU to 1v8 and measure with the mode you want to use the usb the current on the SB26 , which is there to do this. :)
Then you know it for real.
Just to decide, how to supply it : take any small LDO 3v3 , they all can deliver > 100mA , so no problem here.
It doesn't matter whether the USB requires 0.5 or 50mA peak current, you are on the safe side.
-- Or lets look to the values from other similar chips, imxRT1050, NXP : USB_OTG1_VBUS ->
5uA at power down, up to max. 25 mA for each active USB interface ; so about same range.
