Nexperia USA Inc. 74AHCT257D,112

Overview

74AHCT257D,112 from Nexperia is a quad 2-input multiplexer with 3-state outputs, designed for digital signal routing in mixed-voltage systems. It features TTL-compatible inputs (VIH = 2.0 V min, VIL = 0.8 V max), operates from 4.5 V to 5.5 V, supports -40 °C to +125 °C ambient range, and delivers propagation delays as low as 3.7 ns (CL = 15 pF, VCC = 5 V). It is used in bus interface logic, data selector circuits, and level-translating I/O expansion in industrial control modules.

For engineers reviewing the 74AHCT257D,112 datasheet, 74AHCT257D,112 pinout, 74AHCT257D,112 application, or 74AHCT257D,112 equivalent, key selection criteria include its TTL-level input compatibility, 3-state output enable timing (ten ≤ 12.0 ns), overvoltage-tolerant inputs up to 5.5 V, and SO16 package thermal performance at extended temperature.

Technical Context

This device implements four independent 2:1 multiplexers sharing a common select (S) and active-low output enable (OE) control line. Each channel routes either of two inputs (nI0/nI1) to its corresponding 3-state output (nY) based on S state, with OE disabling all outputs to high-impedance.

Its TTL-input threshold (VIH = 2.0 V, VIL = 0.8 V) ensures compatibility with legacy 5 V logic families, while overvoltage-tolerant inputs allow safe interfacing with higher-voltage signals up to 5.5 V without external clamping. The non-inverting data path and Schmitt-trigger inputs enhance noise immunity in noisy industrial environments.

Key Specifications

Pinout & Package

74AHCT257D,112 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; pins are spaced at 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74AHC257D,112 and SN74LV257APWR, the 74AHCT257D,112 uniquely balances TTL compatibility, 5 V robustness, and sub-4 ns speed-making it optimal for retrofitting legacy 5 V systems without redesigning level-shifting networks.

Availability

74AHCT257D,112 is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, automotive body control modules, and test equipment signal routing requiring stable component supply across extended temperature and mixed-voltage conditions.

Supply support for 74AHCT257D,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 global semiconductor expert delivering high-performance logic, analog, and MOSFET solutions with focus on efficiency, reliability, and sustainability.

The 74AHCT series targets industrial and automotive applications requiring robust 5 V TTL compatibility, extended temperature operation, and high-noise-immunity logic functions.

FAQ

What is the maximum clock frequency supported by 74AHCT257D,112?

The device does not operate on a clock; it is combinational logic. Its usable data rate is determined by propagation delay (tpd ≤ 9.0 ns max at VCC = 5.5 V, CL = 50 pF) and enable timing. For reliable operation with 50 pF loads, input transitions should be limited to <100 MHz to maintain setup/hold margins.

Can 74AHCT257D,112 interface directly with 3.3 V microcontrollers?

Yes, but only as a receiver: its inputs tolerate 5.5 V, so 3.3 V logic outputs can drive it safely. However, its outputs swing rail-to-rail (0 V to 5 V), so direct connection to 3.3 V-only inputs requires a level shifter or series resistor + clamp diode to avoid overvoltage damage.

Is the 74AHCT257D,112 pin-compatible with older 74LS257 variants?

Yes-pinout matches industry-standard 16-pin SOIC layout for quad 2:1 multiplexers (S, I0/I1 per channel, Y outputs, OE, VCC, GND). However, LS devices draw significantly more current and lack overvoltage tolerance; replacement requires verifying supply stability and noise margin in the target system.

Does 74AHCT257D,112 require external pull-up or pull-down resistors on unused inputs?

No-Schmitt-trigger inputs provide inherent hysteresis and noise immunity. Unused inputs should be tied to VCC or GND to prevent floating states and minimize dynamic power consumption; no external resistors are needed due to low input leakage (≤0.1 μA).