Nexperia USA Inc. 74HCT123PW,112

Overview

74HCT123PW,112 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, -40 °C to +125 °C operating range, and programmable pulse width via external REXT/CEXT networks. It serves as a precision timing element in digital control logic, pulse stretching, debounce circuits, and delay generation where deterministic, extendable output pulses are required.

For engineers reviewing the 74HCT123PW,112 datasheet, 74HCT123PW,112 pinout, 74HCT123PW,112 application, or 74HCT123PW,112 equivalent, this device delivers retriggerable one-shot behavior with Schmitt-triggered A/B inputs, direct active-low reset per channel, and dual independent timing paths - critical for robust edge-sensitive timing in industrial control, power sequencing, and signal conditioning systems.

Technical Context

The 74HCT123PW,112 implements two independent monostable circuits, each with separate negative-edge (nA) and positive-edge (nB) trigger inputs, dedicated reset (nRD), and complementary outputs (nQ/nQ). Pulse width is externally set by REXT and CEXT on pins 7/15 (channel 2) and 14/15 (channel 1), supporting widths from 75 ns (REXT = 5 kΩ, CEXT = 0 pF) up to hundreds of microseconds.

Retriggering extends the output pulse without interruption; a LOW-going edge on nRD terminates it immediately. Schmitt-trigger action on nA/nB inputs ensures immunity to slow-rising signals, while input clamp diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors.

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 SN74LV123APWR, the 74HCT123PW,112 uniquely balances TTL compatibility, industrial temperature resilience, and retriggerable flexibility - making it the optimal choice for upgrading legacy 5 V systems where input voltage margins and robustness outweigh raw speed.

Availability

74HCT123PW,112 is available at Aetrix Electronics and suitable for motor control timing, industrial sensor debounce, and power sequencing requiring stable component supply across automotive and industrial production cycles.

Supply support for 74HCT123PW,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 delivering high-performance, reliable discrete, logic, and MOSFET solutions with focus on efficiency, reliability, and miniaturization.

The 74HCT123 series belongs to Nexperia's industry-standard logic portfolio, designed specifically for robust timing, pulse shaping, and signal conditioning in automotive, industrial, and consumer applications demanding wide temperature operation and noise immunity.

FAQ

What is the minimum external timing capacitor value supported for stable operation?

The datasheet specifies stable operation down to CEXT = 0 pF (with REXT = 5 kΩ), yielding a minimum pulse width of 75 ns. However, for reliable long-term stability and reduced sensitivity to parasitic capacitance, Nexperia recommends CEXT ≥ 100 pF when REXT ≥ 10 kΩ. Pin capacitance at 1REXT/CEXT and 2REXT/CEXT is approximately 7 pF, which must be included in total timing capacitance calculations.

Can both channels share the same REXT/CEXT network?

No - each channel requires its own dedicated REXT and CEXT components. Pins 14/15 serve channel 1; pins 6/7 serve channel 2. Sharing would cause coupling and unpredictable pulse width interaction. The functional diagram and pin description explicitly assign independent timing nodes, and the datasheet application circuits (Fig. 11–13) show separate networks per channel.

How does the reset input (nRD) behave during power-up?

nRD is active-low and edge-triggered: a LOW-to-HIGH transition terminates the output pulse. At power-up, if nRD is left floating or pulled HIGH, the device may generate an unintended output pulse due to internal state uncertainty. Nexperia recommends applying a controlled reset pulse (LOW then HIGH) at power-on, as shown in Fig. 12, to guarantee known initial state and suppress spurious outputs.

Is the TSSOP16 package (SOT403-1) RoHS compliant and lead-free?

Yes - the 74HCT123PW,112 uses Nexperia's standard lead-free, halogen-free, RoHS-compliant TSSOP16 package (SOT403-1). The device meets JEDEC J-STD-020 moisture sensitivity level MSL3 and is qualified for reflow soldering per IPC/JEDEC J-STD-020D. Full compliance documentation is available in Nexperia's product change notices and material declarations.