First, create an equation for V_T that covers both output voltages when the output is high or low. The hysteresis voltage in this network is equal to the difference in the two threshold voltage equations.

Since input bias is typically 1 µA, it is best to choose a value for R₁ and then solve for the required R₂ to provided the needed amount of hysteresis. In this example, a value of 500 Ω was selected to minimize the impact of input bias current on circuit offset voltage. Solving for R₂ provides the equation below. Note that VOD is 350 mV from the EC Table.

VREF can now be solved for using the equation for VINN_LOW or VINN_HI. IN this example, VINN_HI was chosen.

The external hysteresis design is now complete with R₁ = 500 Ω, R₂ = 8.25 kΩ, V_REF = 2.8 V.