This is a system with an ATmega328P.
Using 'Standby' mode, with a regular watchdog wakeup (for a timing 'tick'):
The sleep current consumption is ~ 90ÂµA
Detail of the sleep level:
changing only the sleep mode, to 'Power Down':
detail of the sleep level of just one wake-sleep cycle:
I'm curious about the slow drop-off of the current when entering sleep - is that expected?
Full-size images attached.