74HC123D/AUJ

Overview

The Nexperia 74HC123D/AUJ is a dual retriggerable monostable multivibrator with reset, manufactured by Nexperia. It operates within a supply voltage range of 2.0 V to 6.0 V and supports an ambient temperature range from -40 °C to +125 °C. The device features Schmitt-trigger action on inputs nA and nB for noise immunity and includes clamp diodes for input protection. It provides complementary active HIGH (nQ) and active LOW (nQ) outputs. Pulse width is controlled via external resistor (REXT) and capacitor (CEXT), allowing extension through retriggering or immediate termination via the direct reset input (nRD).

Feature Summary

• Dual retriggerable monostable multivibrator architecture with independent timing control.
• Schmitt-trigger action on edge-triggered inputs ensures tolerance to slow rise and fall times.
• Direct reset input allows immediate termination of the output pulse at any time.
• Integrated input clamp diodes enable interfacing to voltages exceeding VCC using current limiting resistors.

Applications

• Timing generation and pulse width modulation circuits.
• Debouncing switches and eliminating contact bounce in digital systems.
• Frequency division and pulse stretching applications.

Procurement Notes

Verify that the specific ordering suffix 'AUJ' corresponds to the SO16 package (SOT109-1) as documented in the official datasheet. Confirm compliance with RoHS directives and JEDEC standards JESD8C and JESD7A during procurement. Ensure the component meets the specified operating temperature range of -40 °C to +125 °C for your application environment.

Selection Notes

Select this component when a dual-channel monostable multivibrator with Schmitt-trigger inputs is required. It is suitable for CMOS logic families and offers LSTTL pin compatibility. Consider the wide supply voltage range and high noise immunity for robust operation in noisy environments requiring precise pulse timing control.

Part Context

This component belongs to the 74HC/HCT series of high-speed Si-gate CMOS devices. It is designed to be pin-compatible with Low-power Schottky TTL (LSTTL) logic families. The device complies with JEDEC standard no. 7A and is part of Nexperia's extensive portfolio of logic integrated circuits.

Replacement Considerations

Public confirmed substitute part numbers include 74HCT123D-Q100 and 74HC123PW,118. Verify package type and electrical specifications before substitution.

FAQ

How is the output pulse width determined?

The basic output pulse width is programmed by the selection of external components, specifically the external resistor (REXT) and capacitor (CEXT).

Can the output pulse be extended after triggering?

Yes, the basic output pulse width may be extended by retriggering either of the edge-triggered inputs (nA or nB).

What is the function of the nRD input?

The nRD input serves as a direct reset; applying a LOW-going edge to this input terminates the output pulse at any time.