A noninverting comparator with hysteresis requires a two-resistor network, as shown in Figure 39, and a voltage reference (VREF) at the inverting input. When VIN is low, the output is also low. For the output to switch from low to high, VIN must rise to VIN1. Use Equation 4 to calculate VIN1.
When VIN is high, the output is also high. For the comparator to switch back to a low state, VIN must drop to VIN2 such that VA is equal to VREF. Use Equation 5 to calculate VIN2.
The hysteresis of this circuit is the difference between VIN1 and VIN2, as shown in Equation 6.