Single-gate Schmitt-trigger buffer for noisy rails and mixed-voltage boards
It takes a noisy or slow-edge input and delivers a clean, fast push-pull output, making it a standard choice for debouncing switches, squaring up sensor signals, or driving a clock line that's seen better days. The supply range spans 1.65V to 5.5V, so it fits comfortably alongside 1.8V, 2.5V, 3.3V, and 5V logic without a separate level translator. The SOT-23-5 package (SC-74A) takes up minimal board area, useful when you need one extra buffer without dedicating a whole SOIC-14.
The Schmitt-trigger input provides hysteresis, typically around 0.5V at 3.3V supply. That hysteresis rejects noise on a long trace or a slow-rise sensor output, preventing the output from chattering. If you've ever watched a pushbutton bounce on a scope, this is the part that cleans it up without external RC filtering.