always-on domain
Beginner
The small part of the chip that never sleeps. It notices a button press or a message and wakes up the rest.
Novice
The part of a chip that stays powered in every mode. It holds the wake-up logic, timers and the controller that turns the other parts on and off.
Expert
Kept small and built from low-leakage cells. Its signals cross switched domains through always-on buffers, and its leakage sets the device’s floor current in deep sleep.
Explained in Personal and edge devices (Industries).