NXP Semiconductors 74LV251D,118

Overview

74LV251D,118 from NXP Semiconductors (formerly Philips) is an 8-input CMOS multiplexer with true/complement 3-state outputs, operating from 1.0 V to 3.6 V supply, featuring 19 ns typical propagation delay (S₂→Y at V_CC = 3.3 V), 3.5 pF input capacitance, and –40°C to +125°C industrial temperature range - used in digital signal routing for programmable logic controllers and industrial I/O modules.

For engineers reviewing the 74LV251D,118 datasheet, 74LV251D,118 pinout, 74LV251D,118 application, or 74LV251D,118 equivalent, key selection criteria include low-voltage operation down to 1.0 V, dual active-high/active-low outputs enabling cascaded multiplexing, TTL-level compatibility at V_CC ≥ 2.7 V, and SO16 package suitability for space-constrained PCB layouts.

Technical Context

The 74LV251D,118 implements a single-pole, eight-throw analog/digital switch function using Si-gate CMOS technology, with three binary select lines (S₀–S₂) decoding one of eight inputs (I₀–I₇) to Y and Y outputs. Its 3-state enable (OE, active LOW) allows output bus sharing and hierarchical expansion without external gating.

It is pin- and function-compatible with 74HC/HCT251 but optimized for lower V_CC operation, supporting dynamic power calculation via CPD = 44 pF and exhibiting ground bounce < 0.8 V and VOH undershoot > 2 V at V_CC = 3.3 V, critical for noise-sensitive mixed-signal systems.

Key Specifications

Pinout & Package

74LV251D,118 is supplied in a 16-pin plastic small outline package (SO16, SOT109-1), 3.9 mm body width, with standard 1.27 mm pitch and gull-wing leads suitable for reflow soldering.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-input multiplexer applications.

Compared with 74LV251D,118, the 74LV251PW,118 offers identical functionality in a smaller footprint ideal for compact designs, while the SN74LV251AD provides second-source availability with near-identical performance but a narrower maximum operating temperature ceiling.

Availability

74LV251D,118 is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74LV251D,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

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with roots in Philips' pioneering logic IC development.

The 74LV251D,118 belongs to NXP's LV (Low-Voltage) logic family, designed specifically for mixed-voltage system interfacing and energy-efficient digital signal routing in harsh-environment electronics.

FAQ

What is the minimum supply voltage for reliable operation of the 74LV251D,118?

The 74LV251D,118 is guaranteed to function down to V_CC = 1.0 V with input levels referenced to GND or V_CC; DC characteristics are fully specified from V_CC = 1.2 V to 3.6 V. At 1.0 V, propagation delays increase and output drive weakens, but logic functionality remains intact - making the 74LV251D,118 suitable for ultra-low-power wake-up circuits and brown-out tolerant designs.

Does the 74LV251D,118 support TTL-level inputs when powered from 3.3 V?

Yes, the 74LV251D,118 accepts TTL input levels when V_CC is between 2.7 V and 3.6 V: VIH(min) = 2.0 V and VIL(max) = 0.8 V meet standard TTL thresholds. This allows direct connection to 5 V TTL outputs without external level shifters - a key feature confirmed in the Philips datasheet's "Accepts TTL input levels" statement and verified in DC electrical characteristics tables.

What is the purpose of the complementary Y output on the 74LV251D,118?

The complementary Y output on the 74LV251D,118 provides the logical inverse of the true Y output simultaneously, eliminating the need for external inverters in applications requiring both polarities - such as driving differential receivers, enabling active-HIGH and active-LOW control lines, or simplifying combinational logic in glue logic circuits. Both Y and Y are 3-state controlled by the same OE pin.

Can multiple 74LV251D,118 devices be cascaded for more than 8 inputs?

Yes, the 74LV251D,118 supports cascading via its 3-state outputs: when OE is HIGH, both Y and Y enter high-impedance (Z) state, allowing multiple devices to share a common bus. By enabling only one device at a time using decoded OE signals, up to 64 inputs (eight 74LV251D,118 units) can be routed to a single output - a capability explicitly stated in the datasheet's "Both outputs are 3-State for further multiplexer expansion" feature.

Is the 74LV251D,118 pin-compatible with the 74HC251 or 74HCT251?

Yes, the 74LV251D,118 is pin- and function-compatible with the 74HC251 and 74HCT251, as confirmed in the Philips datasheet's "pin and function compatible with 74HC/HCT251" statement. However, it operates at lower V_CC (1.0–3.6 V vs 2.0–6.0 V) and exhibits faster propagation delays at 3.3 V - making it a drop-in upgrade for existing HC/HCT designs migrating to 3.3 V systems, provided OE polarity and timing margins are verified.