What this 74ALS inverting buffer does on the bus
The Texas Instruments SN74ALS540N3 is an octal (8-bit) inverting buffer with 3-state outputs from the 74ALS advanced low-power Schottky family. It takes eight input signals and presents their inverted logic levels at the outputs, with a single output-enable (OE) pin that drives all eight outputs into high-impedance when asserted. This makes it a straightforward bus-interface component for 5 V TTL systems where you need to isolate or invert a data or address bus segment. The 20-pin DIP package (0.300" body width) is a through-hole footprint that fits standard breadboards, prototyping sockets, and legacy PCB layouts.
Output drive and temperature — what limits matter
The output stage is rated for 15 mA sourcing and 24 mA sinking.
Lifecycle and BOM fit
This part is RoHS non-compliant.