Power Consumption: 328P Comparator VS op ap chip

I’m looking to build a very low power PIR circuit and I need an analog comparator. I could use a dedicated low power op amp chip for the comparator and output that to a 328P, or I could use the analog comparator internal to the 328P.

I read about the analog comparator in the datasheet (p243 overview and p51 for minimizing power consumption), but I’m not sure what type of current draw I can expect from the 328p if I used the comparator in the chip. Number of components is irrelevant, I would like to know what to expect for current draw on a full sleep for the 328p with only the comparator active until the comparator causes an interrupt when motion occurs. Or is there a better way to accomplish this? Thanks in advance.

Most PIR outputs are digital (HIGH or LOW), why do you need a comparator?

what type of current draw I can expect from the 328p if I used the comparator in the chip

Figure 30-323 in my copy of the ATmega328P data sheet.

I'm looking to build a very low power PIR circuit

Look for battery operated PIR modules, often used in household alarm systems. They are designed by professional engineers to run for years on two AAA batteries. You probably can't do better than that.