The TC74HC123P is a Dual Retriggerable Monostable Multivibrator with Clear manufactured by Toshiba Semiconductor and Storage. This device contains two independent monostable multivibrators, each capable of producing a stable low or high output pulse of a specific duration when triggered. The retriggerable capability allows the output pulse to be extended if a new trigger pulse arrives before the end of the current pulse duration. The clear input allows for asynchronous resetting of the output pulse.

Applications

• Timing Circuits
• Pulse Generators
• Delay Circuits
• Missing Pulse Detectors
• Frequency Dividers

Features

• Retriggerable Operation
• Wide Range of Output Pulse Widths
• Clear Input for Asynchronous Reset
• Triggering from Leading or Trailing Edge
• Low Power Dissipation
• High Noise Immunity
• Output Drive Capability: 10 LSTTL Loads

Benefits

• Versatile Timing Control: Retriggerable operation provides flexibility in controlling pulse durations based on input trigger frequency.
• Precise Pulse Generation: Allows for accurate generation of pulses with a wide range of widths, adjustable by external components.
• Asynchronous Reset: The clear input enables immediate termination of the output pulse, independent of the trigger input.
• Flexible Triggering: Can be triggered by either the rising or falling edge of the input signal, offering design flexibility.
• Energy Efficient: Low power dissipation makes it suitable for battery-powered and energy-conscious applications.
• Reliable Operation: High noise immunity ensures stable and predictable operation in noisy environments.
• Easy Integration: Can drive multiple LSTTL loads, simplifying interfacing with other logic circuits.

Additional Details

The output pulse width is determined by external resistor (Rext) and capacitor (Cext) values connected to the device. The formula for approximating the pulse width is typically given as Pulse Width ≈ Rext * Cext. Refer to the datasheet for precise calculations and recommended component values.

The TC74HC123P is available in a plastic Dual In-Line Package (DIP). The operating temperature range is generally from -40°C to +85°C. For proper operation, pay attention to the recommended voltage levels and timing characteristics specified in the official Toshiba datasheet. Ensure adequate decoupling capacitors are used to minimize noise on the power supply lines.