SN74HC138AN

Overview

The SN74HC138AN is a single 3-to-8 line decoder and demultiplexer manufactured by Texas Instruments. It operates within a supply voltage range of 2 V to 6 V and features three binary selection inputs (A0, A1, A2) that determine which of the eight outputs is activated. The device utilizes two active-low enable inputs and one active-high enable input to manage operation and facilitate cascading without external logic. It is housed in a 16-pin PDIP package and supports surface mount or through-hole installation styles depending on the specific variant configuration.

Feature Summary

• Integrates three binary selection inputs to decode address signals into one of eight distinct output lines
• Includes dual active-low and single active-high enable inputs to simplify system expansion and reduce external component requirements
• Designed for high-performance memory decoding and data routing applications with propagation delays comparable to low-power Schottky TTL

Applications

• Memory address decoding in high-performance storage systems
• Data routing and distribution networks
• Industrial control logic circuits

Procurement Notes

Verify the exact ordering suffix against the manufacturer's current documentation to confirm package type and environmental compliance. Ensure the selected variant matches the required operating temperature range and pin configuration for the target PCB layout. Cross-reference the datasheet revision history to confirm compatibility with existing design specifications before finalizing procurement orders.

Selection Notes

Select this component when a standard 3-to-8 decoding function is required with CMOS compatibility. Consider the SN74HC138AN specifically for through-hole assembly needs due to its PDIP packaging. Evaluate the enable input configuration to ensure it aligns with the system's control logic requirements for efficient cascading or demultiplexing operations.

Part Context

This part belongs to the SN74HC138 series of high-speed silicon-gate CMOS decoders. The HC logic family offers low power consumption while maintaining switching speeds similar to low-power Schottky TTL. This specific model represents the standard commercial grade version available in a traditional dual in-line package format suitable for prototyping and general-purpose digital logic designs.

Replacement Considerations

Compatible substitutes include CD74HC138 from Texas Instruments and equivalent parts from other manufacturers such as ON Semiconductor or NXP. Verify pinout compatibility and electrical characteristics like propagation delay and output drive strength before substitution.