SN74HCS21DR

Inverter Gates Overview

The SN74HCS21DR is a dual 4-input AND gate with Schmitt-trigger inputs manufactured by Texas Instruments. It operates within a supply voltage range of 2 V to 6 V and supports an ambient temperature range from -40°C to +125°C. The device features balanced CMOS push-pull outputs capable of ±7.8 mA drive current at 5 V. Propagation delay ranges from 8 ns to 52 ns depending on the supply voltage. Input capacitance is typically 5 pF, and power dissipation capacitance per gate is 10 pF.

Inverter Gates Feature Summary

• Schmitt-trigger inputs provide hysteresis for noise rejection and tolerance to slow input signals
• Balanced CMOS push-pull outputs allow similar sourcing and sinking currents
• Low power consumption with typical supply current of 100 nA
• Wide operating voltage range supporting 2 V to 6 V

Inverter Gates Applications

• Combining power good signals
• Enabling digital signals
• Driving system controller reset pins

Inverter Gates Procurement Notes

Verify the specific package type matches the design requirements, as the SN74HCS21 family includes both SOIC (D) and TSSOP (PW) options. Confirm that the ordering suffix corresponds to the desired packaging format, such as tape and reel quantities. Ensure compliance with RoHS standards and check for any automotive qualified versions if high-reliability applications are required.

Inverter Gates Selection Notes

Select this component when noisy or slow-rising input signals are present, as standard CMOS gates may oscillate under these conditions. The extended temperature range makes it suitable for industrial environments. Consider the propagation delay specifications relative to the system clock speed and ensure the output drive capability meets the load requirements without exceeding absolute maximum ratings.

Inverter Gates Part Context

The SN74HCS21 belongs to the HCS logic family, which combines low power consumption with Schmitt-trigger functionality. This series is designed to handle challenging signal integrity issues common in modern digital systems. The DR suffix indicates the SOIC-14 package variant, distinguishing it from other package options like the TSSOP available within the same logical function family.

Inverter Gates Replacement Considerations

SN74HCS21PWR is a direct functional equivalent packaged in TSSOP-14 instead of SOIC-14.