What this 4 x 2:1 multiplexer is for
The Texas Instruments SN74HCT157DT is a quad 2:1 multiplexer from the 74HCT family, packing four independent 2-input multiplexers into a single 16-SOIC package. It selects one of two 4-bit data sources based on a common select line, with a strobe input to force all outputs low. The 4.5 V to 5.5 V supply range makes it a direct drop-in for 5 V TTL or CMOS logic systems, and the 6 mA source/sink output drive handles standard fan-out to a handful of LSTTL or HCT loads without a buffer. The single-supply 5 V rail simplifies power distribution on mixed-voltage boards — no second regulator needed for the mux logic.
5 V logic compatibility — the main fit question
Yes, this part is built for 5 V logic. The supply range of 4.5 V to 5.5 V covers the full 5 V ±10% tolerance window, so it runs cleanly off a standard 5 V rail. Input thresholds are TTL-compatible (VIL max 0.8 V, VIH min 2.0 V at 5 V), meaning it will reliably interpret signals from older 5 V TTL families as well as 5 V CMOS outputs that swing rail-to-rail.
The 16-SOIC (0.154" body width, 3.90 mm) is a common, easy-to-inspect footprint.
There is no last-time-buy or end-of-life notice on this part. For BOM planning, that means no forced redesign cycle from obsolescence in the near term. Sourcing is through independent distribution — we can quote against an RFQ with current availability and pricing confirmed at the time of your request.