Hello @Transidico,
This window configures the power level at which the ADC will operate, as described in its description. In the case of the MCXA153, the ADC supports two power modes, Low Power Mode and High Power Mode. Each of which requires specific configurations (such as clock source selection, register bit settings, etc.). For more details, refer to section 40.3.1 “Power Control Mode” in the RM.
Additionally, I highly recommend reviewing the AN14390, which provides a detailed explanation of the ADC peripheral and can be very helpful for understanding its operation.
BR
Habib