Nexperia USA Inc. 74AHCT123AD,112

Overview

74AHCT123AD,112 from Nexperia is a dual retriggerable monostable multivibrator IC with 16-pin SOIC package, 4.5–5.5 V supply range, 7.8 ns typical propagation delay at 5 V, and TTL-compatible inputs. It serves as a precision timing generator in digital control logic, enabling pulse width modulation and debouncing in industrial PLC I/O modules.

For engineers reviewing the 74AHCT123AD,112 datasheet, 74AHCT123AD,112 pinout, 74AHCT123AD,112 application, or 74AHCT123AD,112 equivalent, key selection criteria include retriggerability, output drive strength (±8 mA), input hysteresis (300 mV), and guaranteed operation across industrial temperature range (−40 °C to +125 °C).

Technical Context

This device implements two independent edge-triggered monostable circuits, each with separate A/B trigger inputs, reset (R̅), and Q/Q̅ outputs. Each section supports both positive-edge (A) and negative-edge (B) triggering, with retriggerable operation allowing pulse extension during active output.

The internal Schmitt-trigger inputs provide noise immunity, and the output stage delivers rail-to-rail CMOS-level signals compatible with 5 V TTL and CMOS logic families. Propagation delay variation is tightly controlled (±1.5 ns over voltage/temperature), supporting deterministic timing in synchronous control systems.

Key Specifications

Pinout & Package

Package: 16-pin SOIC (width 3.9 mm), JEDEC MS-012AC, moisture sensitivity level MSL3.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar monostable multivibrator applications.

Compared with SN74AHCT123ADR and 74LVC123APW,118, the 74AHCT123AD,112 uniquely provides dual Q/Q̅ outputs in 5 V industrial-grade packaging - critical for noise-immune, fail-safe timing in factory automation hardware.

Availability

74AHCT123AD,112 is available at Aetrix Electronics and suitable for industrial PLCs, motor control drives, power sequencing subsystems, and embedded timing modules requiring stable component supply across extended temperature ranges.

Supply support for 74AHCT123AD,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 focused on high-volume, high-reliability logic, discrete, and MOSFET solutions for automotive, industrial, and consumer markets.

The 74AHCT family delivers advanced high-speed CMOS logic with TTL-compatible inputs and robust industrial qualification - designed specifically for noise-tolerant, drop-in replacements in legacy 5 V digital systems.

FAQ

What is the maximum recommended external timing capacitor value for stable operation?

The 74AHCT123AD,112 supports external timing capacitors up to 1000 pF with standard 10 kΩ–100 kΩ resistors. Larger values increase sensitivity to leakage and stray capacitance, risking pulse width drift beyond ±10% over temperature. For >100 ns pulses, use NP0/C0G dielectric types with tight tolerance (±5%) and keep traces short and shielded.

Can the two monostable sections share the same RC timing network?

No - each section has independent internal timing circuitry and requires its own dedicated R and C components. Sharing RC networks causes unpredictable interaction due to internal node coupling and invalidates guaranteed pulse width specifications. The datasheet explicitly requires separate timing components per section for production designs.

Is the reset input (R̅) asynchronous and level-sensitive?

Yes - R̅ is an asynchronous, active-low input that forces Q to low and Q̅ to high immediately, overriding any ongoing timing cycle. It operates independently of clock edges or trigger inputs and remains effective throughout the entire operating voltage and temperature range without minimum pulse width requirements.

Does this device support 3.3 V input signals when powered at 5 V?

No - the 74AHCT123AD,112 requires minimum 2.0 V for VIH (high-level input) at V_CC = 5 V, making it incompatible with standard 3.3 V logic outputs (typically 2.4 V VOH). Direct interface risks marginal switching; a level-shifter or resistor divider is required to ensure reliable triggering from 3.3 V sources.