74HCT221DB,118

Overview

The 74HCT221DB,118 is a dual non-retriggerable monostable multivibrator manufactured by Nexperia USA Inc. under the NXP brand portfolio. It operates within a supply voltage range of 4.5V to 5.5V and features two independent circuits in a 16-SSOP package. Each multivibrator includes active LOW-going edge input (nA) and active HIGH-going edge input (nB), with nB inputs providing hysteresis for improved noise immunity. The device supports overriding reset functionality to terminate output pulses and is specified for operation between -40°C and +125°C.

Feature Summary

• Dual non-retriggerable monostable multivibrator configuration
• Active LOW-going edge input (nA) and active HIGH-going edge input (nB)
• Overriding reset capability to terminate output pulse
• nB inputs feature hysteresis for improved noise immunity

Applications

• Pulse generation and timing circuits
• Debouncing switches or contacts
• Delay line applications
• Frequency division circuits

Procurement Notes

Verify component authenticity through authorized distributors due to potential counterfeit risks. Confirm RoHS compliance status and check for specific manufacturing date codes if required for long-term production stability. Ensure proper handling procedures are followed during storage and assembly to maintain device integrity.

Selection Notes

Select this component when dual independent monostable timing functions are required in a single package. Consider the HCT logic family compatibility with TTL levels for interface simplicity. Evaluate the SSOP package constraints against PCB space requirements and thermal management needs for the specific application environment.

Part Context

This part belongs to the 74HCT series of high-speed CMOS logic devices, designed for compatibility with low power Schottky TTL (LSTTL) standards. The 74HCT221 specifically provides dual monostable multivibrator functionality, offering a compact solution for timing applications compared to discrete implementations.

Replacement Considerations

Direct pin-compatible replacements include other 74HCT221 variants from different manufacturers such as Texas Instruments SN74HCT221N. Verify electrical characteristics and package dimensions before substitution to ensure circuit compatibility.