Quad NOR gate in the 74ALS family — active, through-hole, no second-source risk
The SN74ALS02AN is a Texas Instruments quad 2-input NOR gate from the 74ALS series, packaged in a 14-pin DIP (0.300", 7.62mm) for through-hole assembly. Lifecycle status is Active and ROHS3 compliant — no end-of-life notice, no RoHS transition to manage.
Each of the four NOR gates sources 400µA and sinks 8mA at the output. This is the standard 74ALS drive capability: it can fan out to 20 standard TTL loads without external buffering, but the 400µA source limit means driving a 50pF load at speed requires the full 8mA sink for the low-to-high transition on the falling edge. Maximum propagation delay is 12ns at 5V and 50pF load. This is the worst-case figure across temperature and supply — typical delay is lower, but the 12ns ceiling sets the timing budget for the slowest path. For a 20 MHz clock, 12ns leaves 38ns of the 50ns period for setup and hold; at 33 MHz it tightens to 18ns margin, which is still workable in most combinatorial logic chains. Input logic thresholds are 0.8V low and 2V high — standard TTL-compatible levels. The 0.8V low threshold is forgiving of ground bounce, but the 2V high threshold means a 3.3V logic output driving this gate must be level-shifted or the high-level noise margin drops to 1.3V.
Package and board integration — 14-DIP through-hole, still a viable footprint
Supplied in Tube packaging. For high-volume pick-and-place, the DIP format requires a tube feeder or manual insertion; there is no tape-and-reel option for this package variant.