DM74ALS138M

Overview

The DM74ALS138M is a 3-to-8 line decoder/demultiplexer manufactured by onsemi, utilizing an advanced oxide-isolated, ion-implanted Schottky TTL process. It operates within a supply voltage range of 4.5V to 5.5V and features three enable inputs (one active-HIGH, two active-LOW) for simplified cascading. The device provides fully buffered inputs with Schottky diode clamping to suppress ringing. It is housed in a 16-lead Small Outline Integrated Circuit (SOIC) package.

Feature Summary

• Designed for high-performance memory decoding and data routing applications requiring short propagation delays
• Incorporates three enable inputs to simplify system expansion and eliminate external inverters
• Features fully buffered inputs presenting only one normalized load to the driving circuit
• Utilizes Schottky-clamped inputs to suppress line-ringing and simplify system design

Applications

• High-performance memory decoding systems
• Data transmission and routing systems
• Cascaded decoder implementations up to 24 or 32 lines

Procurement Notes

Verify component authenticity through authorized distributors or direct manufacturer channels. Confirm datasheet revision status and lot traceability upon receipt. Ensure storage conditions comply with moisture sensitivity level requirements prior to soldering. Validate pinout alignment against the M16A package drawing before integration into PCB layouts.

Selection Notes

Select this component when low power dissipation and high-speed switching are required in standard 5V logic environments. The SOIC package suits surface-mount designs needing narrow footprint compatibility. Consider the specific enable input configuration if expanding decoder arrays without additional logic gates. Verify thermal performance constraints relative to the specified junction-to-ambient thermal resistance values.

Part Context

This part belongs to the 74ALS logic family, characterized by reduced power consumption compared to standard 74LS devices while maintaining comparable speed. The 'M' suffix specifically denotes the 16-lead SOIC package variant. Originally produced by Fairchild Semiconductor, the product line was transferred to onsemi following corporate acquisitions.

Replacement Considerations

SN74ALS138AN from Texas Instruments offers functional equivalence in a PDIP package.