2024-05-23 10:53 PM
2024-05-26 02:04 AM
Dear @Zaim01 ,
indeed that part number is designed to be used with external SMPS topology to reduce further the power and thus bypassing our internal LDO.
The part number MCU having P or PTR suffix in the marking, i.e. STM32L412RBT6P) and it is connected directly to Vcore power line (Core, Memories and Digital peripherals supply).
Vdd12 power supply line can be used to bypass the internal LDO regulator when using an external SMPS.
In such a case you need to apply there voltage in range 1 .. 1.32V.
It doesn't require any external decoupling capacitor and it does not support any external load.
In case you would like to use an internal LDO, please keep this line unconnected.
More information on that you can find within dedicated application note, AN4978 "Design recommendations for STM32L4xxxx with external SMPS, for ultra-low-power applications with high performance"
Hope it helps you .
STOne-32