Comparators

Notes

1. Number of comparators in one IC.
2. Maximum input current.  Ideally zero.
3. Maximum current that the output can sink.  Ideally infinite.  The devices are open-collector or open-drain and therefore cannot source any current.
4. How close to ground the output voltage can go.  Ideally zero, often one diode drop above.
5. The maximum output voltage.  Since comparators are open-collector or open-drain, the output is in a high-impedance state when the device is "on", so the output must be pulled up with a resistor.  There is a maximum voltage that the output pin can be pulled up to without damaging the device.
6. The chip must be powered from supplies between these two extremes.