What this hex Schmitt-trigger inverter does on the board
The Texas Instruments SN74LS14DR is a hex inverter with Schmitt-trigger inputs from the 74LS bipolar low-power Schottky family. It packs six independent inverters into a 14-SOIC package, each with a single input and a Schmitt-trigger hysteresis that cleans up slow or noisy edges — useful for debouncing switches, squaring up oscillator waveforms, or interfacing with sensors that produce ragged transitions.
Key ratings and what they mean for the BOM
Supply range of 4.75V to 5.25V ties it to classic 5V TTL rails — not a 3.3V or 1.8V logic part, so confirm your rail before fitting it into a mixed-voltage design. Propagation delay of 22ns at 5V with a 15pF load sets the timing budget for the signal path. In a 10 MHz clock chain you lose about a quarter-cycle per gate; cascading multiple stages needs a timing analysis. Output drive is rated 400µA sourcing and 8mA sinking — enough to drive a standard TTL load or a low-power LED indicator, but not a high-current relay or bus without a buffer. Input logic thresholds are 0.5V low and 1.9V high, with the Schmitt hysteresis providing noise immunity of about 1.4V typical. That margin handles a slowly rising RC waveform or a long PCB trace with crosstalk.
Temperature grade and environment
Rated 0°C to 70°C commercial temperature range, so it fits indoor equipment, office appliances, and benchtop instrumentation — not an engine bay or outdoor telecom cabinet without additional thermal management.
Lifecycle and sourcing posture
The SN74LS14DR carries an Active lifecycle status from TI, with ROHS3 compliance.