STM32L562CE 48-pin 1.8V USB

[driftycelery]

Hello,

As I understand from datasheet if you use 64, 81, 100, 132 or 144 pin package there is separated power supply domain for USB transceivers, i.e. VDDUSB which should be connected between 3.0-3.6V or connected to VDD if USB is not used.

However, 48-pin package does not have VDDUSB, so the question - if I am design my board around 1.8V will this MCU in 48-pin package work as intended, i.e., USB will enumerate and etc. ? Or I should switch to 3.3V, use level shifters from 1.8V to 3.3V?

Thanks in advance!

[STOne-32 · Accepted solution]

Dear @driftycelery ,

First, Welcome in STM32 Community and happy to see you contributions to all members.

Indeed, VDDUSB rail is dedicated to power the embedded USB PHY to 3,3Volts to be compliant with USB signaling generally in 1,8Volts VDD , when USB is plugged from an external LDO with the VBUS (5Volts) and keeping all MCU and board at 1,8V. Therefore in this case your suggestion is right to select another package with VDDUSB. That pin is bonded internally to VDD . Having an external level shifter will not help as you can not power the internal PHY . 
Hope it helps you .

Ciao

STOne-32

[driftycelery]

Dear STOne-32,
Thank you for the confirmation! I will change the package!