SN74LS221DRE4

Overview

The SN74LS221DRE4 is a dual non-retriggerable monostable multivibrator manufactured by Texas Instruments. It belongs to the 74LS logic family and operates within a supply voltage range of 4.75 V to 5.25 V. The device features two independent circuits housed in a 16-SOIC package with a width of 3.90 mm. It provides complementary outputs and includes a clear function. The propagation delay is specified at 45 ns, with output currents of 400 µA for high state and 8 mA for low state. Operating temperature ranges from 0°C to 70°C.

Feature Summary

• Dual non-retriggerable monostable multivibrator configuration
• Complementary outputs available for each circuit
• Integrated clear function for pulse control
• Schmitt-trigger inputs for noise immunity

Applications

• Timing delays
• Pulse generation
• Waveform shaping
• Frequency division

Procurement Notes

Verify the specific ordering suffix 'E4' indicates RoHS compliance and green material status as per Texas Instruments documentation. Confirm the package type matches the required PCB footprint. Ensure the operating environment stays within the specified commercial temperature limits. Check for any recent product change notices affecting assembly or sourcing locations.

Selection Notes

Select this component when dual independent timing channels are required in a compact surface-mount format. The LS series offers standard TTL compatibility. Verify that the load capacitance requirements do not exceed the datasheet specifications to maintain accurate pulse widths. Consider thermal dissipation if multiple units operate simultaneously on the same board.

Part Context

This part is an enhanced version of the standard SN74LS221DR, distinguished by the 'E4' suffix which typically denotes environmental compliance. It is part of the broader 74LS221 family used in digital systems requiring precise single-shot pulse generation. The device serves as a fundamental building block for sequential logic applications.

Replacement Considerations

SN74LS221DR is a direct functional equivalent without the environmental suffix. SN74LS122 is a similar monostable but contains only one circuit per package. SN74LS123 offers retriggerable functionality instead of non-retriggerable behavior.