Nexperia USA Inc. 74HCT257DB,112

Overview

74HCT257DB,112 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. Used in microcontroller peripheral interfacing and address/data bus multiplexing.

For engineers reviewing the 74HCT257DB,112 datasheet, 74HCT257DB,112 pinout, 74HCT257DB,112 application, or 74HCT257DB,112 equivalent, key selection criteria include TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max), propagation delay of 16 ns (typ) at 4.5 V, 3-state output drive capability (±6 mA), and SO16 package compatibility with legacy PCB footprints.

Technical Context

This device implements four independent 2:1 multiplexers sharing one select line (S) and one global 3-state output enable (OE). Each multiplexer routes either I0 or I1 to its Y output based on S level, while OE controls high-impedance state for all four outputs simultaneously.

Input clamping diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors. The design supports direct connection to system buses due to symmetrical output drive strength, rail-to-rail VOH/VOL performance, and low ICC (8 μA typ at 5.5 V).

Key Specifications

Pinout & Package

74HCT257DB,112 is packaged in SO16 (SOT109-1), a plastic small outline package with 16 leads and 3.9 mm body width. Pin 1 is index-marked; pin 16 is VCC; pin 8 is GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HCT257DB,112, the D,112 variant offers identical performance in the same SO16 footprint but with older packaging logistics, while SN74HCT257N trades industrial reliability and speed for through-hole convenience-making the DB,112 optimal for volume production in space-constrained, noise-sensitive embedded systems.

Availability

74HCT257DB,112 is available at Aetrix Electronics and suitable for industrial control systems, test instrumentation, legacy microcontroller expansion, and bus arbitration applications requiring stable component supply across extended temperature ranges.

Supply support for 74HCT257DB,112 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 leading Dutch semiconductor manufacturer specializing in high-performance, energy-efficient logic, analog, and discrete components for industrial, automotive, and consumer markets.

The 74HCT series targets TTL-compatible logic integration in mixed-signal embedded systems, emphasizing robustness, wide operating margins, and long-term supply stability for mission-critical applications.

FAQ

What is the maximum clock frequency supported by 74HCT257DB,112?

The device does not operate on a clock signal-it is combinational logic. Its usable data rate depends on propagation delay (16 ns typ at 4.5 V) and system setup/hold timing. For reliable operation with clean edges, input transitions should remain slower than 139 ns/V (Δt/ΔV) to avoid metastability, supporting effective data rates up to ~30 MHz in well-designed PCB layouts with controlled impedance and proper termination.

Can 74HCT257DB,112 interface directly with 3.3 V microcontrollers?

No-its TTL-compatible inputs require VIH ≥ 2.0 V, which 3.3 V logic meets, but its minimum VCC is 4.5 V. Operating below 4.5 V violates recommended conditions and risks unreliable switching. To interface with 3.3 V controllers, use level translators such as TXB0104 or select a 3.3 V–compatible mux like 74LVC257PW.

Is the 74HCT257DB,112 pin-compatible with 74HC257 variants?

Yes-identical pinout and function across 74HC257, 74HCT257, and 74ACT257 families in SO16. However, HC variants require CMOS-level inputs (VIH = 3.15 V min at 4.5 V), making them incompatible with TTL sources unless buffered. HCT's TTL input thresholds ensure drop-in replacement where input drive matches.

Does 74HCT257DB,112 support hot insertion or live bus swapping?

Not inherently-its input clamp diodes protect against brief overvoltage during insertion, but uncontrolled hot-plug events can exceed absolute maximum ratings (e.g., VI > VCC + 0.5 V). For true hot-swap capability, add series current-limiting resistors (≥1 kΩ) and ensure OE is held HIGH until power stabilizes, per Nexperia's application guidance in AN10734.