Hi,
I’m using an STM32L052 with LQFP32 package, VDD = 1,8V.
According to the datasheet:
“VDD_USB = 1.65 to 3.6V: external power supply for USB transceiver, USB_DM (PA11)
and USB_DP (PA12). To guarantee a correct voltage level for USB communication
VDD_USB must be above 3.0V. If USB is not used this pin must be tied to VDD or VSS.
On packages without VDD_USB pin, VDD_USB voltage is internally connected to VDD
voltage”
Since in the LQFP32 package VDD_USB is internally connected to VDD, it is therefore powered at 1,8V in my design.
As expected, the USB interface does not operate when I connect the board to a PC and risk of damage because D+ and D- tied to 1,8V
Could you please confirm that the internal USB PHY cannot operate correctly at 1,8 V, and that USB operation requires VDD ≥ 3.0 V even when VDD_USB is internally tied to VDD ?
If so, what would be the recommended workaround for designs that operate the MCU at 1,8 V ?
Thanks in advance for your clarification.
