Nexperia USA Inc. 74HCT257DB,118

Overview

74HCT257DB,118 from Nexperia is a quad 2-input multiplexer with 3-state outputs, designed for bus-oriented data routing in TTL-level logic systems. It features a single common select input (S), active-low 3-state output enable (OE), CMOS-compatible power efficiency, and operates across 4.5 V to 5.5 V supply at -40 °C to +125 °C. It enables dynamic signal selection in microcontroller peripheral interfaces and memory address decoding.

For engineers reviewing the 74HCT257DB,118 datasheet, 74HCT257DB,118 pinout, 74HCT257DB,118 application, or 74HCT257DB,118 equivalent, key selection criteria include TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max), propagation delay of 13–30 ns at VCC = 4.5 V, 3-state output drive capability (±6 mA), and SO16 package compatibility with legacy PCB footprints.

Technical Context

The 74HCT257DB,118 implements four independent 2:1 multiplexers sharing one select line (S) and one global output-enable (OE). Each channel routes either I0 or I1 to its corresponding Y output based on S state, with outputs entering high-impedance when OE is HIGH.

Its TTL-compatible inputs accept standard 5 V logic levels, while outputs deliver rail-to-rail CMOS swing with guaranteed VOH ≥ 3.98 V and VOL ≤ 0.26 V at IO = ±6 mA. The device supports system bus interfacing directly due to 3-state outputs and input clamp diodes enabling overvoltage-tolerant input conditioning via external current-limiting resistors.

Key Specifications

Pinout & Package

74HCT257DB,118 is housed in a plastic small outline package (SO16, SOT109-1) with 16 leads and 3.9 mm body width. Pin 1 is index-marked; pin 8 is GND; pin 16 is VCC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-input multiplexer applications.

Compared with 74HCT257DB,118, the 74HCT257D,118 offers identical performance in a functionally interchangeable SO16 package, while the SN74HCT257N lacks clamp diodes and latch-up certification - making it unsuitable for ruggedized industrial deployments despite matching basic logic behavior.

Availability

74HCT257DB,118 is available at Aetrix Electronics and suitable for industrial control systems, motor drive signal routing, FPGA-based memory expansion, and microcontroller peripheral consolidation requiring stable component supply across extended temperature ranges.

Supply support for 74HCT257DB,118 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Nexperia is a global semiconductor expert focused on high-volume, high-reliability logic, discrete, and MOSFET solutions, with manufacturing rooted in process technology leadership and automotive-grade quality systems.

The 74HCT257DB,118 belongs to Nexperia's 74HCT logic family, engineered specifically for TTL-compatible interfacing in industrial and consumer systems where robustness, low power, and wide temperature operation are essential.

FAQ

What is the maximum clock frequency supported by the 74HCT257DB,118?

The device does not operate on a clock; it is asynchronous. Its usable data rate is determined by propagation delay (13–30 ns at VCC = 4.5 V) and transition time (5–12 ns), supporting reliable signal routing up to approximately 30 MHz in well-terminated 15 pF bus environments.

Can the 74HCT257DB,118 interface directly with 3.3 V logic?

No - its inputs require TTL-level thresholds (VIH ≥ 2.0 V), but it is not 3.3 V tolerant. Driving it from a 3.3 V source risks marginal VIH compliance and undefined behavior. A level shifter or 5 V buffer is required for reliable 3.3 V → 5 V interface.

Is the 74HCT257DB,118 pin-compatible with the 74HC257DB,118?

Yes - both share identical SO16 pinout, pin functions, and package dimensions. However, the 74HC257DB,118 uses CMOS-level inputs (VIH = 3.15 V min at VCC = 4.5 V), so substituting it for 74HCT257DB,118 in TTL-driven systems may cause logic misreads.

Does the 74HCT257DB,118 require external pull-up or pull-down resistors on unused inputs?

Unused inputs must be terminated - either to VCC or GND - because floating CMOS inputs cause increased supply current, noise susceptibility, and potential oscillation. OE and S are particularly sensitive; leaving them unconnected risks unintended output enable or channel selection.