LM139J Analogue Comparator, Quad, Precision, 4 Comparators, 1.3 µs, ± 1V to ± 18V. The LM139J is a low power low offset Voltage Quad Comparator designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage.