Nexperia USA Inc. 74AHCT123AD-Q100J

Overview

74AHCT123AD-Q100 from Nexperia is a dual retriggerable monostable multivibrator with independent reset, designed for precise pulse generation and extension in automotive timing circuits. It operates from 4.5 V to 5.5 V, supports -40 °C to +125 °C ambient range, delivers programmable pulse widths (90–115 μs typical with 0.01 μF/10 kΩ), and features TTL-level inputs with overvoltage-tolerant pins up to 5.5 V. It is used in engine control unit (ECU) signal conditioning and ADAS sensor pulse shaping.

For engineers reviewing the 74AHCT123AD-Q100 datasheet, 74AHCT123AD-Q100 pinout, 74AHCT123AD-Q100 application, or 74AHCT123AD-Q100 equivalent, this page provides verified functional context, SO16 package layout, automotive-grade timing specifications, and validated alternatives for pulse-width modulation, glitch suppression, and delay generation in safety-critical systems.

Technical Context

This device implements two independent monostable circuits, each with dual edge-triggered inputs (nA: negative-edge, nB: positive-edge), direct asynchronous reset (nRD), and external R/C-programmable output pulse width. Retriggering extends the active output period without requiring pulse termination - enabling duty-cycle flexibility up to 100 %.

Each circuit provides complementary outputs (nQ active HIGH, nQ active LOW), Schmitt-trigger input hysteresis for noise immunity, and input voltage tolerance beyond VCC (to 5.5 V), allowing interoperability across mixed-voltage domains in automotive ECUs and body control modules.

Key Specifications

Pinout & Package

74AHCT123AD-Q100 uses the SO16 plastic small outline package (SOT109-1), 16-pin, 3.9 mm body width, with gull-wing leads and industry-standard pin 1 index marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74AHC123AD-Q100 and SN74LV123AQPWRQ1, the 74AHCT123AD-Q100 uniquely combines TTL-compatible inputs, sub-15 ns reset response, and AEC-Q100 Grade 1 validation - making it the only choice for safety-critical automotive monostable functions requiring deterministic, low-latency pulse termination.

Availability

74AHCT123AD-Q100 is available at Aetrix Electronics and suitable for engine control units, ADAS sensor interfaces, and body control modules requiring stable component supply across extended temperature ranges and automotive lifecycle commitments.

Supply support for 74AHCT123AD-Q100 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, reliable discrete, logic, and MOSFET devices optimized for automotive, industrial, and consumer applications.

The 74AHCT123AD-Q100 belongs to Nexperia's automotive-qualified logic portfolio, engineered specifically for robust timing functions in harsh environments - emphasizing noise immunity, wide temperature operation, and AEC-Q100 compliance.

FAQ

What is the minimum external REXT value supported for stable operation?

The datasheet specifies REXT ≥ 1 kΩ for VCC > 3.0 V. Using values below 1 kΩ risks excessive current draw through the internal timing node and may cause pulse width instability or increased propagation delay variation. For 5 V operation, 1.2 kΩ is the recommended minimum to ensure margin against process variation and temperature drift.

Can both monostable circuits share the same REXT/CEXT network?

No - each circuit requires its own dedicated REXT and CEXT components. Pins 1REXT/CEXT (15) and 1CEXT (14) serve Circuit 1; Pins 2REXT/CEXT (7) and 2CEXT (6) serve Circuit 2. Sharing would couple timing behavior and prevent independent retriggering or reset, violating the functional isolation guaranteed in the datasheet.

Is the nRD pin truly asynchronous, and does it override retriggering?

Yes - nRD is fully asynchronous and overrides all ongoing timing states. A LOW-going edge on nRD forces immediate termination of the current output pulse (nQ goes LOW, nQ goes HIGH) regardless of whether nA/nB retrigger events are pending or active. This behavior is confirmed in Table 3 (Function Table) and Fig. 7 (reset timing waveform).

How does overvoltage tolerance on inputs affect PCB layout?

Because inputs tolerate up to 5.5 V independently of VCC, no series resistors or clamping diodes are required when interfacing with 5 V sensors - simplifying layout. However, GND and VCC decoupling must still be placed within 5 mm of the IC to maintain noise immunity, especially given the Schmitt-trigger hysteresis that relies on clean local supply references.