A comparator may produce “chatter” (multiple transitions) at the output when there are noise or signal variations around the reference threshold; this causes the output to change states in rapid random successions as the comparator input goes above and below the threshold of the reference. This usually occurs when the input signal is moving very slowly across the switching threshold of the comparator. This problem can be prevented by using the internal hysteresis feature of the comparator or by the addition of external hysteresis.
The TLV3603-Q1 has a LE/HYS pin that allows for variable internal hysteresis depending on the resistor value connected between the pin and VEE, where increasing the resistance decreases the hysteresis to a minimum level.
Since the TLV3601-Q1 and TLV3602-Q1 only have a minimal amount of internal hysteresis, external hysteresis can be added in the form of a positive feedback loop. A non-inverting comparator with hysteresis requires a two-resistor network and a voltage reference (VREF) at the inverting input, as shown in Figure 8-6.