74HC123 Dual Retriggerable Monostable Multivibrator IC (74123) DIP 16 Package

74HC123 Dual Retriggerable Monostable Multivibrator IC (74123) DIP 16 Package

The 74HC123 is a Dual Retriggerable Monostable Multivibrator IC (also known as a one-shot pulse generator) from the 74HC (High-Speed CMOS) logic family.

Each section of the IC operates as an independent monostable circuit that produces a single output pulse of a specified duration whenever it is triggered. The pulse width (time duration) is determined by an external resistor (Rext) and capacitor (Cext) connected to the IC.

Because it is retriggerable, a new trigger input received before the previous timing interval ends will extend the output pulse duration, making it ideal for timing, delay, and pulse-stretching applications.

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Specifications:-

• Package Type:            DIP
• Multivibrator Type:      Retriggerable Monostable
• Voltage Rating:           4.75 to 5.25V
• Current Rating:           8mA Output Current
• Temperature Rating:    0 to 70 Deg C
• Number of Pins:          16
• Propagation Delay:      23ns

Functional Description

• Each section of the 74HC123 generates a pulse of fixed width in response to a trigger.
• Trigger inputs (A and B) allow flexibility for edge or level triggering.
• Clear input (CLR) resets the output immediately when LOW.
• The pulse width (tW) is determined by the Rext × Cext time constant:
• tW?0.45×Rext×Cextt_W ? 0.45 \times R_{ext} \times C_{ext}tW??0.45×Rext?×Cext?
• When retriggered before the pulse ends, the IC extends the current pulse instead of starting a new one.

Applications

• Pulse Generation
• Timing Delay Circuits
• Pulse Stretchers / Pulse Width Modulators
• Debouncing Mechanical Switches
• Frequency Divider or Edge Detector
• Missing Pulse Detection
• Monostable Multivibrator Circuits
• Timing Control in Communication Systems

74LS123-ic-datasheet