Nexperia USA Inc. 74HC123D,652

Overview

74HC123D,652 from Nexperia is a dual retriggerable monostable multivibrator in SO16 package, providing programmable pulse width via external R_EXT/C_EXT, edge-triggered inputs (nA/nB), direct reset (nRD), and complementary outputs (nQ/nQ). It operates from 2.0 V to 6.0 V, supports -40 °C to +125 °C, and enables precise timing control in digital logic interfaces and debounce circuits.

For engineers reviewing the 74HC123D,652 datasheet, 74HC123D,652 pinout, 74HC123D,652 application, or 74HC123D,652 equivalent, this device serves as a flexible, low-power timing element where adjustable pulse extension, Schmitt-trigger input tolerance, and TTL/CMOS-compatible variants (74HCT123D) are critical selection criteria.

Technical Context

The 74HC123D implements two independent monostable circuits, each with separate negative-edge (nA) and positive-edge (nB) trigger inputs, active-low reset (nRD), and complementary outputs (nQ/nQ). Pulse width is externally set by R_EXT and C_EXT on pins 15/14 (Channel 1) and 7/6 (Channel 2), supporting typical widths from 75 ns to >450 μs.

Schmitt-trigger action on nA/nB inputs ensures robust operation with slow-rising signals; clamp diodes allow overvoltage-tolerant interfacing via current-limiting resistors. The reset path provides sub-77 ns propagation delay (V_CC = 4.5 V), enabling deterministic pulse termination independent of timing capacitor discharge state.

Key Specifications

Pinout & Package

74HC123D,652 is housed in a plastic small outline package (SO16, SOT109-1), 16-pin, 3.9 mm body width, with gull-wing leads and standard JEDEC MS-012 footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HCT123D,653, the 74HC123D,652 offers broader supply flexibility and lower ICC, while SN74LV123AD trades extended temperature and voltage range for higher speed and drive - making the 74HC123D optimal for general-purpose industrial timing where robustness and compatibility outweigh raw speed.

Availability

74HC123D,652 is available at Aetrix Electronics and suitable for switch debouncing, serial bus timing, PWM generation, and power sequencing requiring stable component supply across automotive, industrial control, and embedded instrumentation applications.

Supply support for 74HC123D,652 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 logic, analog, and discrete components optimized for efficiency and miniaturization.

The 74HC123D belongs to Nexperia's industry-standard 74HC logic family, designed for robust, low-power digital timing and signal conditioning in harsh environments and long-lifecycle products.

FAQ

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

The datasheet specifies grounding pins 6 (2CEXT) and 14 (1CEXT) externally to GND for minimum noise. While C_EXT can be 0 pF, stable pulse width control requires ≥10 pF due to inherent pin capacitance (~7 pF). For reliable retriggering below 100 ns, use C_EXT ≥ 22 pF with R_EXT ≤ 5 kΩ.

Can both monostable channels operate independently without crosstalk?

Yes - the 74HC123D integrates two fully isolated monostable circuits sharing only V_CC and GND. No internal signal coupling exists between channels; propagation delays, pulse widths, and retrigger behavior are independent. Layout best practice is to route timing components (R_EXT/C_EXT) separately with dedicated ground returns.

How does the reset input (nRD) interact with an ongoing retriggered pulse?

nRD terminates the output pulse immediately upon detection of a LOW-going edge, regardless of whether the pulse was initiated or extended by prior nA/nB triggers. The monostable enters reset state and remains there until the next valid trigger; no race condition or metastability occurs, as confirmed by the function table and Fig. 9 waveform.

Is the 74HC123D,652 compatible with 3.3 V microcontroller GPIOs?

Yes - at V_CC = 3.3 V, VIH = 2.31 V (70 % of V_CC) and VIL = 0.99 V (30 % of V_CC), matching standard 3.3 V CMOS logic thresholds. Output VOH = 3.15 V (min) and VOL = 0.26 V (max) at I_O = 4 mA ensure reliable interfacing with 3.3 V receivers without level shifting.