We would like to power the VDD33 domain of an STM32WB0 device (STM32WB05KZ) from an external 3.3V source and the other domains from an external 1.8V source. In theory, it should be possible - by supplying 1.8V to VDDSD in SMPS BYPASS mode, or directly to VFBSD in SMPS OFF mode. However, it is not clear if the SMPS' input (VDDSD) is isolated from VDDIO (the power diagram in the datasheet shows there is a connection). Please clarify if it is possible to use the described configuration.
