What this 4 x 2:1 multiplexer brings to the bus
The Texas Instruments SN74F157AD is a single-supply 5 V multiplexer that routes one of two 4-bit data sources to a common output, configured as four independent 2:1 selector channels. It belongs to the 74F family, which means it runs at the faster propagation delays typical of the F series — useful for gluing together address or data buses in 5 V logic systems where speed matters but a full bus switch is overkill.
The rated output current is 1 mA sourcing (high) and 20 mA sinking (low). That 20 mA sink capability is typical for 74F parts and lets the outputs drive a reasonable fan-out of standard TTL loads — roughly 10 LSTTL inputs per channel — without external buffers. Just don't expect to drive LEDs or relay coils directly off the output pins without a transistor.
Package and footprint — 16-SOIC surface mount
No thermal pad or exposed paddle — just the standard SOIC land pattern.
ROHS3 compliance is confirmed, so it passes EU RoHS and similar global substance restrictions without a waiver.