What this 3:8 decoder does on your board
The SN74AHCT138N is a single 1-of-8 decoder/demultiplexer from TI's 74AHCT family — you feed it a 3-bit binary address and it pulls one of eight outputs low (active-low outputs). It runs on a single 4.5V to 5.5V supply, so it's a direct fit for 5V TTL or CMOS logic systems without level shifting.
Through-hole package and breadboard fit
Housed in a 16-DIP (0.300", 7.62mm) through-hole package, this part is a natural for prototyping — you can drop it into a solderless breadboard or a DIP socket without a soldering iron. The 8mA output drive per pin is enough to light a standard LED or drive a logic input, but don't expect it to switch a relay coil directly.
Active production — no obsolescence worry
No end-of-life notice, no last-time-buy deadline — you can design it into a new BOM or replenish an existing line without supply-chain panic. Sourced per RFQ against your quantity; confirm current pricing and lead time at quote.