SN74LVC138AD

Overview

The SN74LVC138AD is a 3-line to 8-line decoder and demultiplexer from the Texas Instruments LVC logic family. It operates within a supply voltage range of 1.65 V to 3.6 V, supporting low-voltage digital systems. The device features three binary address inputs and eight active-low outputs, enabling precise signal routing. It includes two active-low and one active-high enable inputs for flexible control. Packaged in a 16-pin SOIC-Narrow (SOIC-16) surface-mount format, it ensures compatibility with standard PCB layouts while maintaining high-speed performance suitable for portable applications.

Feature Summary

• Provides decoding and demultiplexing functions via three binary address lines controlling eight distinct output channels.
• Incorporates dual active-low and single active-high enable inputs to manage chip activation states effectively.
• Supports operation across a wide low-voltage power supply spectrum ranging from 1.65 V to 3.6 V.

Applications

• Address decoding in memory-mapped I/O systems
• Demultiplexing data streams in communication interfaces
• Control logic for peripheral selection in embedded devices

Procurement Notes

Verify the specific suffix against official documentation, as ordering codes may indicate variations in packaging or environmental compliance. Confirm the package type matches design requirements, as variants exist in different footprints. Ensure the revision level aligns with existing inventory to prevent integration issues. Cross-reference the manufacturer part number with authorized distributors to guarantee authenticity and traceability throughout the supply chain.

Selection Notes

Select this component when designing circuits requiring low-power consumption and high switching speeds within constrained voltage environments. The LVC series offers improved noise immunity compared to older logic families. Consider the SOIC-Narrow package for space-constrained boards. Evaluate the enable input configuration to ensure it matches the system's control logic polarity requirements before finalizing the schematic.

Part Context

This device belongs to the SN74LVC138A series, representing Texas Instruments' Low-Voltage CMOS technology. It serves as a direct functional replacement for legacy 74LS138 designs but with significantly reduced power dissipation and faster propagation delays. The series is widely utilized in battery-operated equipment due to its efficient voltage handling capabilities and robust performance characteristics under varying load conditions.

Replacement Considerations

Compatible substitutes include SN74LVC138ADGVR and SN74LVC138APW, provided pinouts and electrical specifications remain identical. Verify that alternative packages do not alter thermal or mechanical constraints. Ensure any cross-brand equivalents maintain the same 3-to-8 decoding functionality and voltage tolerance levels.