74HC221DB,118

Overview

The 74HC221DB,118 is a dual non-retriggerable monostable multivibrator manufactured by Nexperia. It operates within a supply voltage range of 4.5 V to 5.5 V and features Schmitt-trigger inputs for noise immunity. The device generates output pulses defined by external timing components using the relationship tW = 0.7 × CEXTREXT. It includes active LOW reset inputs (nRD) to terminate pulses early. The component supports operating temperatures from -40 °C to +125 °C and provides ESD protection exceeding 2000 V (HBM).

Feature Summary

• Dual non-retriggerable monostable multivibrator architecture with independent pulse generation.
• Schmitt-trigger action on nB inputs ensures jitter-free triggering from slow transition rates.
• Direct reset capability allows immediate termination of the output pulse via active LOW inputs.
• CMOS low power dissipation combined with high noise immunity characteristics.

Applications

• Timing delay circuits requiring precise pulse width control.
• Debouncing switches or contacts to eliminate signal bounce effects.
• Pulse shaping and conversion of irregular input signals into uniform pulses.

Procurement Notes

Verify that the specific ordering suffix matches the required package type and temperature range. Confirm RoHS compliance status through official manufacturer documentation before integration. Ensure design accounts for the specified absolute maximum ratings to prevent permanent damage during operation or power-down sequences.

Selection Notes

Select this component when dual independent monostable functions are required in a single package. Verify compatibility with TTL logic levels if interfacing with legacy systems. Consider the external timing resistor and capacitor accuracy as primary factors limiting overall pulse stability rather than internal circuit variations.

Part Context

This device belongs to the 74HCT series of CMOS logic integrated circuits. It is designed for standard digital applications requiring reliable monostable behavior. The SO16 plastic small outline package facilitates surface-mount assembly. It serves as a functional replacement for older discrete timer solutions in compact designs.

Replacement Considerations

Check datasheets for pinout compatibility when substituting with other monostable multivibrators. Verify that alternative devices support the same supply voltage range and trigger input requirements. Ensure thermal performance meets application demands under similar load conditions.