NXP Semiconductors N74F257AN,602

Overview

N74F257AN,602 from Philips Semiconductors is a quad 2-line to 1-line non-inverting multiplexer with 3-state outputs, designed for digital data routing in TTL-compatible systems. It features 4 independent 2:1 mux channels, common select (S) and active-low output enable (OE), 4.3 ns typical propagation delay (I0/Y), 12 mA typical supply current, and operates at 5 V ±10% across commercial temperature range (0°C to +70°C). Used in bus arbitration and data path selection in legacy industrial control logic.

For engineers reviewing the N74F257AN,602 datasheet, N74F257AN,602 pinout, N74F257AN,602 application, or N74F257AN,602 equivalent, key selection considerations include its 3-state output drive capability (±24 mA IOL/IOH), input loading (1.0 FAST unit load), high-impedance disable timing (tPZH/tPLZ ≤ 8.5 ns), and compatibility with 74F-series fan-out and noise margins.

Technical Context

The N74F257AN,602 implements four identical 2-input multiplexers sharing one Select (S) line and one Output Enable (OE) input. Each channel routes either I0n or I1n to Yn based on S level, with true (non-inverting) output logic and simultaneous 3-state control via OE.

Its architecture supports wired-OR bus configurations when multiple devices share a common data bus - outputs enter high-impedance state when OE is high, preventing contention. Propagation delays are asymmetric: tPLH/tPHL from I0/I1 to Yn is faster (≤7.0 ns max) than from S to Yn (≤10.5 ns max), reflecting internal gating structure.

Key Specifications

Pinout & Package

Package: 16-pin plastic DIP (SOT38-4), 300 mil width, through-hole mounting.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2:1 multiplexer applications.

Compared with SN74F257N, N74F257AN,602 offers identical electrical behavior and sourcing continuity from Philips' original design lineage; versus 74ACT257PC, it trades speed/power for guaranteed 74F-family interoperability and legacy board compatibility without voltage translation.

Availability

N74F257AN,602 is available at Aetrix Electronics and suitable for bus arbitration logic, data path selection, legacy system bus expansion, and logic state monitoring interfaces requiring stable component supply and long-term obsolescence mitigation.

Supply support for N74F257AN,602 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

Philips Semiconductors (now NXP Semiconductors) was a leading European semiconductor manufacturer known for robust industrial logic families and automotive-grade ICs.

The 74F257A belongs to the 74F Fast TTL logic series, engineered for high-speed digital systems requiring improved speed-power trade-offs over standard 74LS while maintaining TTL voltage compatibility.

FAQ

What is the maximum clock/data rate supported by the N74F257AN,602?

The N74F257AN,602 is not a clocked device but a combinational multiplexer. Its maximum usable data rate depends on propagation delay and system setup/hold timing. With tPLH/tPHL ≤ 7.0 ns and tPZH/tPLZ ≤ 8.5 ns, it supports reliable operation in 25 MHz bus systems when used with appropriate load capacitance (CL = 50 pF) and termination. The N74F257AN,602 does not specify a clock frequency rating because it has no internal clock - timing is governed solely by input transition rates and output loading.

Is the N74F257AN,602 pin-compatible with the 74F258A?

No, the N74F257AN,602 is not pin-compatible with the 74F258A. While both are quad 2:1 multiplexers, the 74F258A provides inverting outputs, resulting in different internal logic and distinct pin assignments - particularly for output terminals. The N74F257AN,602 uses Ya–Yd for true outputs, whereas the 74F258A outputs are complemented. Substitution requires PCB redesign and logic inversion verification.

Does the N74F257AN,602 support mixed-voltage interfacing (e.g., 3.3 V inputs)?

No, the N74F257AN,602 is a 5 V-only Fast TTL device. Its input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) and absolute maximum ratings (VIN = –0.5 V to +7.0 V) do not guarantee reliable operation with 3.3 V logic levels. Driving it from 3.3 V sources may result in marginal or failed recognition of HIGH inputs. For mixed-voltage systems, use 74ACT257 or level-shifting buffers instead of the N74F257AN,602.

What is the recommended decoupling for the N74F257AN,602?

A 100 nF ceramic capacitor placed as close as possible to the VCC (pin 16) and GND (pin 8) pins is the minimum recommended decoupling for the N74F257AN,602. For boards with multiple 74F devices or high-frequency switching, add a 4.7 µF tantalum or aluminum electrolytic capacitor near the power entry point. This suppresses supply rail noise induced by simultaneous 3-state output transitions, which can exceed 20 mA peak current per device and cause VCC droop or ground bounce affecting adjacent logic.

Can the N74F257AN,602 be used in place of a 74LS257?

Yes, the N74F257AN,602 is a functional and pin-compatible upgrade for the 74LS257 in most applications. It offers faster propagation delay (4.3 ns vs. ~15 ns), higher output drive (±24 mA vs. ±8 mA), and improved noise immunity due to tighter input thresholds. However, its higher ICC (12 mA typ vs. ~20 mA max for LS) and faster edge rates may increase system EMI - verify layout integrity and ensure adequate power distribution before replacement. The N74F257AN,602 retains identical pinout and logic function.