It's a dual op-amp package by Analog Devices, (AD8532), using one amp as a unity gain comparator in a fast power fail detect circuit. It drives through a 1k2 resistor to GP0 on the processor.

Probe pin 2 = DC input voltage (nominal car battery voltage, ie. "12v")
pin 3 = 3V power line for processor/RAM/FLASH.

Output is on pin 1.