SN74ALS138ADR

Overview

The SN74ALS138ADR is a high-speed ALS logic decoder/demultiplexer manufactured by Texas Instruments. It features three address inputs and eight active-low outputs, enabling the selection of one of eight output lines based on binary input codes. The device operates within a supply voltage range of 4.5 V to 5.5 V and includes two active-high and one active-low enable inputs for system expansion. Packaged in a 16-pin SOIC surface-mount format, it offers a propagation delay of 22 ns and supports through-hole or SMD installation styles with an operating temperature range from 0°C to +70°C.

Feature Summary

• Provides decoding functionality for three binary inputs to activate one of eight distinct output lines simultaneously.
• Incorporates multiple enable inputs to facilitate cascading and complex system addressing without external gating components.

Applications

• Address decoding for memory arrays in embedded systems
• Demultiplexing data streams in digital communication circuits
• Control signal routing in industrial automation equipment

Procurement Notes

Verify the specific suffix 'ADR' indicates the tape-and-reel packaging variant rather than tube packaging when sourcing. Confirm that the manufacturer designation aligns with Texas Instruments specifications to ensure compatibility with existing design files. Check for RoHS compliance status as required by regional regulations before finalizing procurement orders.

Selection Notes

Select this component when high-speed switching is required alongside low power consumption typical of the ALS series. Ensure the application environment remains within the specified 0°C to +70°C operational temperature limits. Verify that the 16-pin SOIC footprint matches the printed circuit board layout constraints and soldering capabilities available in the manufacturing process.

Part Context

This part belongs to the SN74ALS138A family of decoders, representing an advancement over standard TTL logic with improved speed and reduced power dissipation. The 'ADR' suffix specifically denotes the reel-packaged version suitable for automated assembly processes, distinguishing it from the 'AN' through-hole variant while maintaining identical electrical characteristics.

Replacement Considerations

Direct substitutes include other SN74ALS138 variants with compatible pinouts and electrical parameters. Verify package type differences between reel and tube options if replacing across packaging formats.