Six open-collector inverters in a 14-SOIC
The Texas Instruments SN74ALS05ADR packs six independent inverter gates with open-collector outputs into a 14-SOIC package. Open-collector means the output transistor pulls low to ground but floats high — you supply the pull-up resistor to whatever voltage the load needs, up to the transistor's breakdown. That makes this part useful for wired-OR bus structures, level-shifting a 5 V logic output to a higher-voltage load, or driving an LED or relay coil directly without a separate buffer.
Sink current and pull-up resistor — the real design choice
Each output sinks up to 8 mA when low. That figure directly sets the minimum pull-up resistor value: R = V_pullup / 8 mA. A 5 V pull-up needs at least 625 Ω; a 12 V pull-up, 1.5 kΩ. Go lower and the output can't pull the line low enough to register a valid logic 0. The propagation delay of 54 ns at 5 V with a 50 pF load includes the RC time constant of the pull-up resistor and the load capacitance — a larger resistor slows the rising edge, so balance speed against power for your bus.
Supply and temperature — 5 V logic, 0 to 70 °C
Not rated for automotive or extended industrial environments; for those, look at the SN74HCS14QDRQ1 which covers -40°C to 125°C.