Dual 4:1 multiplexer on a 5V rail
The SN74ALS153D is a dual 4:1 multiplexer from Texas Instruments' 74ALS family, packing two independent 4-input multiplexers into a single 16-SOIC package. It selects one of four data sources per multiplexer based on a common select bus, making it a straightforward choice for data routing in 5V logic systems. The supply range is 4.5V to 5.5V, single-rail only, so it fits legacy 5V buses but not mixed-voltage or 3.3V domains.
Output drive and fan-out limits
Output drive is rated 2.6 mA source and 24 mA sink. The 24 mA sink is typical for 74ALS and can drive up to 10 standard TTL loads; the source side is weaker, so check the input current of the downstream device before committing the BOM line. No special MSL handling beyond standard Level 1 — no bake required before reflow unless the tube has been exposed to high humidity.