The 74LVC14A is a low-power hex Schmitt trigger with inverting buffers that can be driven from either 3.3 V or 5 V devices. It is generally used as wave and pulse shapers for high noise environments ...
More undocumented applications for the 555 ‘oscillator:’ Not all applications oscillate as we will see. Most are knowledgeable about common CMOS logic inverters and Schmitt triggers such as the 74HC04 ...