Microcontroller Always ON domain
Always on domain: Power is present.
Wake-up pads: Wake the MCU from sleep mode.




The reference on the first datasheet, always on domain, means the electronic is always powered. You cannot selectively power-off this section.

The wakeup pads are for waking up the device from sleep mode (MCU).

Sleep mode and power are two different things. Power means you physically have a voltage present, while sleep is that the CPU, Memory, and others while being powered, doesn't do anything to save power.



PWM During sleep mode will really depend on which MCU you are using. You need to find MCU which contains a hardware PWM module that can operate during sleep. Some MCU has this functionality like the PIC family from Microchip.

Another way to generate a PWM during sleep is to use a GPIO and a timer, set the timer so that the device wakes up each time the pin state has to be changed, this will likely be less efficient than the solution above.