Nexperia USA Inc. 74HCT251D,652

Overview

74HCT251D,652 from Nexperia is an 8-input TTL-compatible CMOS multiplexer with complementary outputs (Y and Y), 3-state output enable (OE), and 3-bit binary select inputs (S0–S2). It operates from 4.5 V to 5.5 V, delivers propagation delay as low as 19 ns (VCC = 5 V, CL = 15 pF), and supports industrial temperature range (−40 °C to +125 °C). It is used in digital logic routing, data selector circuits, and address/data bus management in embedded control systems.

For engineers reviewing the 74HCT251D,652 datasheet, 74HCT251D,652 pinout, 74HCT251D,652 application, or 74HCT251D,652 equivalent, key selection considerations include TTL-level input compatibility, dual complementary outputs, OE-controlled 3-state operation, and SO16 package thermal performance at extended temperature.

Technical Context

The 74HCT251D,652 implements a single 8:1 multiplexer with non-inverting data path and active-low output enable. Its select logic decodes S2:S0 (LSB first) to route one of eight inputs (I0–I7) to Y, while Y provides the inverted signal - enabling simultaneous true/complement output delivery without external inverters.

Input clamping diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors. The device complies with JEDEC JESD7A (2.0–6.0 V) and JESD8C (2.7–3.6 V), and meets HBM ESD >2000 V and CDM >1000 V per JS-001/JS-002.

Key Specifications

Pinout & Package

74HCT251D,652 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; leads are gull-wing, surface-mount compatible, with 1.27 mm pitch and JEDEC MS-012 compliance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8:1 multiplexer applications.

Compared with SN74HCT251N and 74LVX251M, the 74HCT251D,652 uniquely combines SO16 thermal robustness, guaranteed 5 V TTL compatibility, and complementary outputs - making it optimal for space-constrained, high-temperature, and legacy-interface-critical applications.

Availability

74HCT251D,652 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive ECU signal routing, and microcontroller peripheral expansion requiring stable component supply across extended temperature and long product lifecycles.

Supply support for 74HCT251D,652 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, analog, and MOSFET solutions for automotive, industrial, and consumer markets.

The 74HCT251D,652 belongs to Nexperia's 74HCT logic family - engineered for TTL-compatible interfacing in 5 V systems where noise immunity, low static power, and extended temperature operation are critical design requirements.

FAQ

What is the maximum clock frequency supported by the 74HCT251D,652?

The 74HCT251D,652 does not operate on a clock signal - it is combinational logic. Its usable switching rate depends on propagation delay and system setup/hold timing. With 19 ns typical In→Y delay at 5 V and 15 pF load, it supports reliable data routing up to approximately 25 MHz in well-designed synchronous systems where select inputs are stable before propagation completes.

Can the 74HCT251D,652 drive a 50 pF capacitive load reliably?

Yes. The datasheet specifies dynamic characteristics at CL = 50 pF, including tpd = 22 ns (max) and tt = 15 ns (max) at VCC = 4.5 V. Output drive capability (IO = ±4 mA) and low output impedance ensure signal integrity into 50 pF loads typical of PCB traces and CMOS inputs without external buffering.

Is the Y output truly complementary to Y, or is it buffered separately?

Y and Y are internally generated complementary outputs - Y is the direct multiplexed signal, and Y is its logically inverted version produced by an on-die inverter. Both share the same propagation delay path (within 1 ns), ensuring precise phase opposition required for differential sampling and latch control without external components.

Does the 74HCT251D,652 require external pull-up or pull-down resistors on unused inputs?

No. Unused inputs (I0–I7, S0–S2, OE) may float, but doing so increases ICC and susceptibility to noise-induced switching. For guaranteed static operation, tie unused inputs to VCC or GND. OE should be pulled LOW if permanently enabled; tied HIGH if permanently disabled. No external resistors are needed due to internal input structure - but best practice mandates defined logic states.