74LS123 Dual Retriggerable Monostable Multivibrator | TTL Logic | DIP-16

Description

The 74LS123 is a dual retriggerable monostable multivibrator IC, commonly known as a “one-shot” timer. It provides stable pulse-width control, where the output pulse duration is determined by an external timing resistor ($R_{ext}$) and timing capacitor ($C_{ext}$).

This device features three trigger inputs per multivibrator: two active-LOW ($\overline{A}$) and one active-HIGH (B). These allow for flexible triggering on either rising or falling edges. Because it is retriggerable, receiving an additional trigger pulse during the timing cycle will restart the pulse, extending the output duration. This makes the 74LS123 ideal for watchdog timers, signal debouncing, and pulse-shaping applications.

Note: Product images are shown for reference only. The actual product may vary in appearance, manufacturer marking, or logo depending on stock availability.

Features

• Dual independent monostable multivibrators
• Retriggerable functionality for extended pulse widths
• Edge-triggered: 2 active-LOW and 1 active-HIGH trigger inputs per section
• Standard TTL (74LS) logic levels
• DIP-16 through-hole package (Note: While the description mentions SMD, 74LS series ICs are standardly DIP; please verify your board requirements)

Benefits

• Excellent for noise rejection and missing-pulse detection
• Precise timing control using simple R-C components
• Flexible trigger inputs simplify interface with various sensors/switches
• Proven, reliable TTL technology for industrial environments

Applications

• Pulse-Width Modulation (PWM) generation
• Watchdog timer monitoring
• Mechanical switch debouncing
• Missing-pulse detection
• Time-delay circuits

Package Includes

• 1 x 74LS123 Dual Retriggerable Monostable Multivibrator IC (DIP-16 Package)

Specifications