MOSFET Pair Big MOSFETS Small MOSFETS Mixed MOSFETS
Label on diagram P2_7 P2_5 P2_4 P2_6 P1_23 P1_22
Digital output pin 2.7 2.5 2.4 2.6 1.23 1.22
Power Input Between P2_7 and P2_5 Between P2_6 and P1_23 Taken from VBB
Size Big Big Small Small Big Small
Maximum current 12A 12A 0.5A* 0.5A* 12A 0.5A*
Used by default for Heated bed First hotend heater Fan Second hotend heater

*While the datasheet says it can handle ~5A, it should not be used for anything but low-current fans, at least at 12V. Trying to run a hotend off of the small MOSFETs will destroy them (experimentally proven at 12V).