SN74AHC123AD

Overview

The SN74AHC123AD is a dual retriggerable monostable multivibrator from the Texas Instruments AHC logic series, housed in a 16-pin SOIC package. It operates within a supply voltage range of 2V to 5.5V and supports an operating temperature range of -40°C to +85°C. The device features Schmitt-trigger circuitry on inputs A, B, and CLR to accommodate slow input transition rates. Propagation delays are specified at 24.1 ns maximum for CL = 50 pF at VCC = 3.3V, and 16 ns maximum for CL = 50 pF at VCC = 5V. Quiescent current is typically 4 µA.

Feature Summary

• Dual retriggerable monostable multivibrators designed for edge triggering from active-high or active-low gated logic inputs.
• Schmitt-trigger circuitry on A, B, and CLR inputs ensures jitter-free triggering with slow input transition rates.
• Glitch-free power-up reset on outputs prevents undefined states during initialization without requiring a reset pulse.
• Overriding clear function allows termination of output pulses early by driving the CLR input low.

Applications

• Pulse generation and timing circuits
• Debouncing switches
• Frequency division

Procurement Notes

Verify the obsolete status of the SN74AHC123AD before procurement. Confirm that the specific SOIC-16 package variant meets mechanical constraints. Ensure compatibility with the recommended operating conditions, specifically the -40°C to +85°C temperature range and 2V to 5.5V supply voltage. Validate that external timing components align with the datasheet specifications for desired pulse durations.

Selection Notes

Select this component when dual independent monostable circuits are required in a compact SOIC footprint. The AHC series offers high-speed performance suitable for modern digital systems while maintaining CMOS low-power characteristics. Consider the SN74AHC123ADR as an alternative active production version if tape-and-reel packaging is preferred over tube packaging.

Part Context

This device belongs to the SNx4AHC123A family of dual retriggerable monostable multivibrators. It shares functional similarities with other members like the SN74AHCT123A but utilizes AHC logic levels rather than HCT TTL-compatible levels. The 'D' suffix denotes the standard 16-pin Small Outline Integrated Circuit (SOIC) package, which is distinct from SSOP, TSSOP, or PDIP variants available within the same product line.

Replacement Considerations

SN74AHC123ADR