3-2-3. Combinational Logic: Schmitt-Trigger Devices

Schmitt-trigger devices
Example: VHC14

A Schmitt-trigger device has a hysteresis band between two input threshold voltages.
The following shows the input and output waveforms of a Schmitt inverter with an input threshold hysteresis.
In the case of an IC with hysteresis, the positive-going threshold voltage (V_P) differs from the negative-going threshold voltage (V_N). For a slowly rising or falling input, an input threshold hysteresis (V_H) helps stabilize the output. Even in the presence of input noise or power supply or ground bounce due to noise, an IC does not produce a false output unless the noise or bounce exceeds the hysteresis width.