Nexperia USA Inc. 74HCT123PW,118

Overview

74HCT123PW,118 from Nexperia is a dual retriggerable monostable multivibrator with independent reset inputs, TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 5.0 V), 16-pin TSSOP package, operating from 4.5 V to 5.5 V, and specified for -40 °C to +125 °C. It generates programmable output pulses via external REXT/CEXT networks and supports pulse extension via edge-triggered retriggering on nA/nB inputs or immediate termination via nRD.

For engineers reviewing the 74HCT123PW,118 datasheet, 74HCT123PW,118 pinout, 74HCT123PW,118 application, or 74HCT123PW,118 equivalent, this device serves as a precise timing element in digital control logic, debounce circuits, and pulse-width modulation interfaces where deterministic delay generation and dynamic pulse stretching are required.

Technical Context

The 74HCT123PW,118 implements two independent monostable circuits, each with Schmitt-trigger inputs on nA and nB (enabling tolerance to slow-rising signals), a direct-reset input (nRD) that terminates output pulses on LOW-going edges, and dual complementary outputs (nQ active HIGH, nQ active LOW). Each stage uses external REXT and CEXT components to set base pulse width, with retriggering capability allowing indefinite pulse extension up to 100 % duty factor.

Its TTL-level input compatibility ensures seamless integration with legacy 5 V logic families, while its CMOS output drive (IO = ±4 mA at VCC = 4.5 V) supports standard load conditions. Propagation delays are tightly specified: tPHL/tPLH = 23–77 ns (VCC = 4.5–5.5 V, CL = 15 pF), and retrigger time trtrig = 110 ns typical (REXT = 5 kΩ, CEXT = 0 pF, VCC = 5.0 V).

Key Specifications

Pinout & Package

TSSOP16 plastic thin shrink small outline package (SOT403-1), 16 leads, body width 4.4 mm, 0.65 mm pitch, exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC123PW,118 and SN74LS123DR, the 74HCT123PW,118 uniquely balances TTL input compatibility, wide temperature range, and low dynamic power - making it optimal for new automotive and industrial designs requiring robust, drop-in timing control without MCU overhead.

Availability

74HCT123PW,118 is available at Aetrix Electronics and suitable for industrial motor control, automotive body electronics, power supply sequencing, and test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74HCT123PW,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

Nexperia is a global semiconductor expert delivering high-performance logic, analog, and MOSFET solutions optimized for efficiency, reliability, and miniaturization in automotive, industrial, and consumer applications.

The 74HCT123 belongs to Nexperia's industry-standard logic family designed specifically for robust, pin-compatible replacements of legacy TTL devices while delivering CMOS power efficiency and extended temperature operation.

FAQ

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

The datasheet specifies stable operation down to CEXT = 0 pF, yielding a minimum pulse width of 75 ns (typical) with REXT = 5 kΩ. However, for precision timing, CEXT ≥ 100 pF is recommended to minimize impact of inherent pin capacitance (~7 pF) and improve repeatability across temperature and voltage.

Can both monostable sections be triggered simultaneously without crosstalk?

Yes - the two monostable circuits are fully independent, sharing only VCC and GND. No electrical crosstalk is observed between sections, as confirmed by layout isolation and functional testing in the datasheet. Simultaneous triggering produces concurrent, non-interfering output pulses.

Is the 74HCT123PW,118 compatible with 3.3 V microcontroller GPIOs?

No - its TTL input thresholds require VIH ≥ 2.0 V, which is met by 3.3 V logic, but its minimum operating VCC is 4.5 V. Direct connection to 3.3 V MCU outputs risks violating input voltage limits (VI > VCC + 0.5 V). A level shifter or 5 V I/O buffer is required.

How does the retrigger time (trtrig) vary with external component values?

trtrig increases with larger REXT and CEXT values. At VCC = 5.0 V, the datasheet provides trtrig = 30 + 0.19 × REXT × CEXT⁰·⁹ + 13 × REXT¹·⁰⁵ (ns), where REXT is in kΩ and CEXT in pF. For REXT = 5 kΩ and CEXT = 0 pF, trtrig = 110 ns typical.