74HCT221D,112

Overview

The Nexperia 74HCT221D,112 is a dual non-retriggerable monostable multivibrator housed in an SO16 (SOT109-1) package. It operates within a supply voltage range of 4.5 V to 5.5 V and supports ambient temperatures from -40 °C to +125 °C. The device features TTL-compatible input levels and includes Schmitt-trigger circuitry on the nB inputs for noise immunity. Pulse width is determined by external timing components using the relationship tW = 0.7 × CEXTREXT. Static characteristics include a maximum low-level output voltage of 0.4 V at 4.0 mA and a high-level output voltage of 3.7 V at -4 mA under worst-case conditions.

Feature Summary

• Dual non-retriggerable monostable multivibrator configuration with independent timing circuits
• Schmitt-trigger action on nB inputs ensures jitter-free triggering from slow transition rates
• Direct active LOW reset inputs allow immediate termination of output pulses
• Pulse width stability achieved through internal compensation, virtually independent of VCC and temperature

Applications

• Timing pulse generation
• Delay line applications
• Frequency division
• Waveform shaping

Procurement Notes

Verify the specific ordering suffix

Selection Notes

Select this component when a dual monostable solution compatible with standard TTL logic levels is required. Ensure the application utilizes external RC networks for timing control and accounts for the specified power-down protection requirements to prevent damage from stored energy in large external capacitors during system shutdown.

Part Context

This part belongs to the 74HCT series of CMOS logic devices manufactured by Nexperia. It is functionally similar to the 74HC221 but optimized for 5 V operation with TTL input thresholds. The 'D' designation indicates the SO16 plastic small outline package variant, while the ',112' suffix typically denotes tube packaging as per manufacturer standards.

Replacement Considerations

Public confirmed substitute part numbers: 74HC221D, 74HCT221D, 74HCT221DB, 74HC221DB.