[bigpooch]

Your opponent is putting in $5 to win $2.75, so technically
since somebody (button or blinds too) needs to defend this
pot AT LEAST about 35.5% of the time (2.75/(5+2.75)), you
probably need to call here since it's likely AA33 is about
in the top 1/3 of your range. In reality, you may have to
defend about 40% of the time in case your opponent is
semibluffing. If AA33 is not in the top 40% of your range
when you open for $2, folding is normal (maybe you only
open for 4xBB with medium two pairs or better).

If you know your opponent's range in this spot, you simply
need some tiny chance that your hand is best before the
draw, or your opponent is capable of paying you off if you
checkraise on the end.