Nexperia USA Inc. 74AHCT123ABQ,115

Overview

74AHCT123ABQ,115 from Nexperia is a dual retriggerable monostable multivibrator with independent reset inputs, TTL-compatible input thresholds (VIH = 2.0 V, VIL = 0.8 V), 16-terminal DHVQFN package (2.5 × 3.5 × 0.85 mm), and operates from 4.5 V to 5.5 V across –40 °C to +125 °C. It generates programmable output pulses via external REXT/CEXT networks and supports pulse extension via edge-triggered retriggering on A/B inputs - used in industrial timing control, power sequencing, and digital debounce circuits.

For engineers reviewing the 74AHCT123ABQ,115 datasheet, 74AHCT123ABQ,115 pinout, 74AHCT123ABQ,115 application, or 74AHCT123ABQ,115 equivalent, key selection criteria include TTL-level input compatibility, retriggerable pulse width control up to 1.15 ms (with 0.1 μF/10 kΩ), direct asynchronous reset latency ≤14.5 ns, and thermal-enhanced DHVQFN packaging for high-density PCB layouts.

Technical Context

This device implements two independent monostable circuits, each with dual-edge-triggered inputs (nA: negative-edge, nB: positive-edge), a dedicated reset input (nRD) that terminates output pulses asynchronously, and Schmitt-triggered inputs for high noise immunity. Pulse width tW is externally set by CEXT and REXT per channel, with typical values of 100–200 ns (CEXT = 28 pF, REXT = 2 kΩ) or 90–115 μs (CEXT = 0.01 μF, REXT = 10 kΩ) at VCC = 4.5–5.5 V.

Each monostable supports retriggering during an active output period, enabling duty-cycle flexibility up to 100 %, and features overvoltage-tolerant inputs (up to 5.5 V) for mixed-voltage interfacing. The DHVQFN16 package (SOT763-1) provides low thermal resistance and no-lead mechanical stability for automated assembly in space-constrained applications.

Key Specifications

Pinout & Package

DHVQFN16 package (SOT763-1) with exposed thermal pad (non-soldered by default); 2.5 mm × 3.5 mm body, 0.85 mm height, 0.5 mm pitch, 16 terminals. Pin 1 index located at top-left corner (see transparent top view in datasheet Fig. 13).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74AHCT123ABQ,115, the TSSOP variant trades thermal performance for assembly flexibility, while the automotive LV part adds qualification rigor at the cost of functional scope and package compatibility - neither offers identical thermal, timing, and layout advantages in high-density industrial designs.

Availability

74AHCT123ABQ,115 is available at Aetrix Electronics and suitable for industrial power sequencing, digital input debounce, automotive sensor signal conditioning, and legacy system timing interface requiring stable component supply across extended temperature ranges.

Supply support for 74AHCT123ABQ,115 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 solutions with focus on efficiency, reliability, and miniaturization.

The 74AHCT123A series belongs to Nexperia's advanced logic portfolio, designed specifically for robust timing generation in industrial automation, automotive subsystems, and infrastructure equipment where retriggerable precision and wide temperature operation are essential.

FAQ

What is the minimum external capacitor value supported for pulse width programming?

The datasheet specifies no lower limit for CEXT; operation is verified down to 28 pF (yielding ~100–200 ns pulses). For stable timing below 10 nF, ensure low-ESR ceramic capacitors and minimize PCB trace inductance. Values <100 pF increase sensitivity to parasitic capacitance and require careful layout per Figure 9.

Can both channels share the same REXT/CEXT network?

No - each channel requires independent REXT and CEXT components. Pins 1REXT/CEXT (13) and 2REXT/CEXT (2) are electrically isolated. Sharing would cause cross-talk and unpredictable pulse widths. Figure 9 explicitly shows separate R–C networks for channel 1 (pins 13, 14, 15) and channel 2 (pins 2, 4, 7).

Is the exposed thermal pad on the DHVQFN package required to be soldered?

No - per datasheet Section 5.1, the thermal pad (terminal 1 index area) has no electrical or mechanical requirement to be soldered. If soldered, it must remain electrically floating or be connected to GND; floating is recommended to avoid unintended ground loops in mixed-signal layouts.

How does the device behave when both nA and nB are asserted simultaneously?

Per Table 3 (Function Table), simultaneous nA = L and nB = H produces a single output pulse - the device treats the combination as a valid trigger event. Retriggering remains possible during the active pulse via either input, and the output state follows the programmed polarity (nQ active LOW, nQ active HIGH).