74HC123D

Overview

The Toshiba Semiconductor and Storage 74HC123D is a dual retriggerable monostable multivibrator implemented in high-speed silicon gate CMOS technology. It features two independent circuits within a single 14-pin SOIC package, offering pin compatibility with the low-power Schottky TTL (LSTTL) 74LS123 series. The device operates on a supply voltage range of 2V to 6V, supporting standard logic levels for both high and low states. Key electrical characteristics include a maximum static current of 1 µA and output drive capabilities of 5.2 mA for both high and low states. Propagation delay is specified at 19 ns when operating at 5V with a 50 pF load. The component is designed for surface-mount installation and functions reliably across an extended industrial temperature range from -40°C to +85°C.

Feature Summary

• Dual-channel architecture providing two independent retriggerable monostable multivibrators in a compact form factor.
• Schmitt-trigger inputs on specific terminals to enhance tolerance against slow-rising or falling input signals.
• Direct reset functionality allows immediate termination of the output pulse via active-low control signals.
• Retriggerable design supports pulse width extension up to 100% duty cycle through repeated triggering events.

Applications

• Timing generation and pulse stretching in digital logic systems
• Debouncing mechanical switches to eliminate contact bounce noise
• Frequency division and pulse width modulation circuitry

Procurement Notes

Verify the manufacturer designation carefully, as the 74HC123D part number is utilized by multiple vendors including Nexperia and STMicroelectronics. Confirm that the specific unit received matches the Toshiba Semiconductor and Storage datasheet specifications regarding propagation delay and package dimensions. Ensure the ordering suffix corresponds to the required tape-and-reel or cut-tape packaging format for your assembly line requirements.

Selection Notes

Select this component when a dual-channel solution is required for timing applications within the 74HC logic family. It serves as a direct drop-in replacement for the 74LS123 in designs needing lower power consumption while maintaining compatible pinouts. Consider the 19 ns propagation delay and 5.2 mA drive strength to ensure signal integrity meets system timing budgets. Verify that the 14-SOIC package fits the available PCB footprint constraints.

Part Context

This device belongs to the 74HC series of high-speed CMOS logic integrated circuits, widely used in general-purpose digital electronics. The 74HC123 specifically addresses the need for precise timing control using external resistors and capacitors. Its compatibility with LSTTL interfaces allows it to bridge older TTL-based designs with modern low-voltage CMOS systems, facilitating gradual technology transitions without complete schematic redesigns.

Replacement Considerations

Cross-reference with other manufacturers' 74HC123 variants such as those from Nexperia or STMicroelectronics. Verify that alternative sources maintain identical pin configurations and electrical parameters, particularly the 2V-6V operating voltage range and 14-SOIC package outline, to ensure functional interchangeability.