SN74AS138N

Overview

The SN74AS138N is a high-speed silicon-gate CMOS 3-to-8 line decoder/demultiplexer manufactured by Texas Instruments. It operates within a supply voltage range of 4.5 V to 5.5 V and features a propagation delay of 22 ns. The device utilizes a 16-pin PDIP package designed for through-hole mounting. It supports an operating temperature range from 0°C to +70°C with a power dissipation rating of 200 mW.

Feature Summary

• High-speed decoding capability via Advanced Schottky logic technology
• Three enable inputs for flexible system expansion and control
• Low power consumption relative to standard TTL equivalents

Applications

• Address decoding for memory arrays
• Demultiplexing data streams in digital systems
• Control signal generation in industrial equipment

Procurement Notes

Verify the specific suffix 'N' confirms the PDIP-16 through-hole package variant. Confirm RoHS compliance status as required by project specifications. Ensure the manufacturer designation matches Texas Instruments to avoid counterfeit components. Validate that the ALS logic family meets the timing requirements of the target circuit design.

Selection Notes

Select this component when high switching speed is critical compared to standard LS or ALS families. The 3-to-8 configuration suits applications requiring multiple output selection from three address lines. Consider the PDIP package only if through-hole assembly processes are mandated. Verify voltage compatibility with existing 5V logic levels in the system architecture.

Part Context

This part belongs to the SN74ALS series, representing Advanced Low-power Schottky logic. It provides faster performance than standard 74LS devices while maintaining lower power consumption than original 74S types. The 138 function code specifically denotes a 3-line to 8-line decoder/demultiplexer topology common in legacy digital designs.

Replacement Considerations

SN74ALS138AN: Identical functional equivalent with PDIP-16 packaging.