Active 4 x 2:1 bus multiplexer for 5V logic systems
The Texas Instruments SN74CBT3257D is a 4 x 2:1 multiplexer/demultiplexer from the 74CBT family, packaged in a 16-SOIC narrow body. It routes one of two 4-bit data sources to a common output under a single select line — the classic function for bus sharing, data-path steering, or signal gating in 5V digital systems.
Supply rail and temperature — the fit decisions
The 4.5V minimum supply is the hard floor: if your 5V rail droops below that during brownout or cold-crank, the switch's internal logic may not hold the correct state. The 5.5V ceiling is the standard 5V ±10% limit, so no extra headroom for a 5% tolerance rail with ripple.
16-SOIC narrow body — what the footprint expects
The supplier device package field confirms 16-SOIC, so the land pattern is the same JEDEC MS-012 variation used by hundreds of logic and interface parts. Surface-mount only; no through-hole variant in this order code.