NXP 74AHC123APW: A High-Speed CMOS Dual Retriggerable Monostable Multivibrator
The NXP 74AHC123APW is a high-performance, dual retriggerable monostable multivibrator fabricated with advanced high-speed CMOS technology. This integrated circuit is engineered to generate precise, stable output pulses of a predetermined duration, which can be accurately controlled by external timing components: a resistor (RT) and a capacitor (CT). It is designed for applications requiring high noise immunity and low power consumption, typical of the AHC family, while operating over a broad voltage range from 2.0 V to 5.5 V.
Each of the two independent monostable circuits within the package features multiple triggering options for maximum design flexibility. They can be activated by a low-to-high transition on a positive-edge triggered input (A) or by a high-to-low transition on a negative-edge triggered input (B). A dedicated active-LOW clear input (CLR) provides an immediate termination of the output pulse, overriding all other inputs, which is critical for systems requiring immediate abort functionality.
A key feature of the 74AHC123 is its retriggerable capability. This allows the timing cycle to be restarted by applying a new trigger pulse before the current output pulse has concluded. Consequently, the output pulse width can be extended indefinitely through repeated triggering, a vital function for debouncing signals or monitoring unpredictable event intervals. If no retriggering occurs, the output pulse duration is precisely defined by the values of the external RT and CT.
The device is characterized by its high-speed operation while maintaining the low quiescent power consumption of CMOS technology. The outputs are balanced to have similar sink and source capabilities, ensuring robust performance when driving loads. The 74AHC123APW is offered in a TSSOP-16 package, making it suitable for space-constrained PCB designs.
ICGOODFIND: The 74AHC123APW from NXP stands out as a versatile and reliable solution for pulse generation and timing control. Its retriggerable functionality, combined with high noise immunity and a wide operating voltage range, makes it exceptionally well-suited for a vast array of applications, including pulse width modulation, frequency multiplication, signal debouncing, and as a timing element in various industrial, automotive, and consumer electronic systems.
Keywords: Retriggerable Monostable Multivibrator, High-Speed CMOS, Pulse Generation, Timing Control, Noise Immunity.
