What are the USB_FS interface power requirements for the STM32L552CE?

[frightless]

I'm designing for a project using the STM32L552CET6 to hold me over until the STM32L4P5CGT6 is in stock. The datasheet (DS12737 Rev4) for the STM32L552xx line describes the interface as available in Table 2.

The reference manual mentions an independent supply for USB. But Figure 10 and Table 21 show the LQFP-48 package as replacing Pin 36's VDDUSB supply with VDD.

I think I can safely assume there's no boost to get 3V on the DP and DM lines for the PHY if the voltage on VDD is lower. I was hoping for a little clarification. Is this supply actually USBVDD, not VDD as in the datasheet? Is the USB peripheral unavailable on the L552CE? Is it only available when VDD > 3.0V? Or does it require external hardware? Any info is appreciated. Thanks!

[TDK · Accepted solution]

The answer is in the reference manual:

The VDDUSB power supply may not be present as a dedicated pin, but to be internally bonded to VDD. For such devices, VDD has to respect the VDDUSB supply range when the USB is used.

So yes, you need VDD=VDDUSB in the range of 3.0-3.6V if you want to use the USB.

[frightless]

D'oh! It's right in the power nets section. Thank you for the insight!