SN74AS27DR

Overview

The SN74AS27DR is a high-speed silicon-gate CMOS logic gate manufactured by Texas Instruments. It contains three independent 3-input positive NOR gates within a single 14-pin SOIC package. The device operates on a supply voltage range of 4.5 V to 5.5 V and supports surface-mount installation. Key electrical characteristics include a low-level output current capability of 20 mA and a high-level output current of -2 mA. The typical propagation delay is 4.5 ns at 5 V with a 50 pF load, ensuring rapid signal processing in digital circuits.

Feature Summary

• Integrates three independent 3-input positive NOR logic functions for complex boolean operations.
• Utilizes advanced AS series technology to achieve high-speed switching performance suitable for demanding digital applications.
• Provides robust drive capability with significant low-level output current sourcing capacity.

Applications

• High-speed digital logic circuit design requiring fast response times
• Computer peripheral interface systems utilizing standard TTL-compatible logic levels
• Industrial control systems needing reliable boolean logic processing

Procurement Notes

Verify the specific suffix 'DR' corresponds to the tape-and-reel packaging format required for automated assembly processes. Confirm that the operating temperature range aligns with the intended environmental conditions of the final product. Ensure compatibility with existing PCB footprints designed for the 14-SOIC package dimensions. Cross-reference the latest manufacturer documentation for any updates regarding lead-free compliance or material declarations before finalizing procurement orders.

Selection Notes

Select this component when system requirements demand faster propagation delays than standard ALS or HC series devices can provide. The AS series offers superior speed-performance power dissipation trade-offs compared to older bipolar technologies. Consider the 20 mA sink current capability if driving multiple loads or capacitive traces without external buffering. Evaluate the 14-SOIC package constraints against available board space and thermal management strategies for dense layouts.

Part Context

This part belongs to the Texas Instruments SNx4AS27 family of high-speed logic gates. The AS (Advanced Schottky) designation indicates the use of Schottky clamping diodes to prevent saturation, thereby reducing storage time and improving switching speeds. This family bridges the performance gap between standard TTL and newer CMOS technologies, offering speed comparable to bipolar parts with lower power consumption.

Replacement Considerations

SN74AS27DRG4 serves as an environmentally compliant alternative within the same functional specification. SN74ALS27 variants offer similar pinouts but with slower propagation speeds and different drive characteristics. SN74HC27 provides a CMOS alternative with wider voltage tolerance but significantly reduced switching speed compared to the AS series.