The basic comparator configuration may oscillate or produce a noisy "chatter" output if the applied differential input voltage is near the comparator's offset voltage. This usually occurs when the input signal is moving very slowly across the switching threshold of the comparator.
This problem can be prevented by the addition of hysteresis or positive feedback.
The hysteresis transfer curve is shown in Figure 8-2. This curve is a function of three components: VTH, VOS, and VHYST:
For more information, please see Application Note SBOA219 "Comparator with and without hysteresis circuit".