LM2901N - LOW POWER QUAD VOLTAGE COMPARATORS. This device consists of four independent precision voltage comparators. All these comparators were designedspecifically to operatefrom a single power supply over a wide range of voltages. Operation from split power supplies is also possible. These comparators also have a unique characteristic in that the input common-mode voltage range includes ground even though operated from a single power supply voltage. Is also used in the first digital Organs and retro Pinball machines. Datasheet: LM2901N