SN74HCT138DRG4

Overview

The SN74HCT138DRG4 is a 3-line to 8-line decoder and demultiplexer manufactured by Texas Instruments. It operates within a supply voltage range of 4.5 V to 5.5 V and features TTL-compatible inputs with low input current. The device incorporates three enable inputs to simplify cascading and data reception, allowing for the implementation of expanded decoders without external inverters. It provides active-low outputs capable of driving up to 10 LSTTL loads. Typical propagation delay is 17 ns at 5 V, supporting high-speed memory decoding and data transmission applications.

Feature Summary

• Incorporates three enable inputs (two active-low, one active-high) to facilitate system expansion and demultiplexing functions.
• Features TTL-voltage compatible inputs designed for integration into high-performance memory-decoding systems.
• Provides active-low outputs capable of driving significant loads while maintaining low power consumption.

Applications

• High-performance memory decoding
• Data routing and transmission systems
• Demultiplexing applications

Procurement Notes

Verify that the component matches the SN74HCT138DRG4 designation, specifically confirming the SOIC-16 package and the G4 suffix indicating lead-free and RoHS compliance. Ensure the operating temperature range aligns with industrial requirements (-40°C to 85°C). Cross-reference the manufacturer's orderable addendum to confirm current production status and availability of the specific tape-and-reel packaging format.

Selection Notes

Select this component when TTL-compatible logic levels are required in CMOS-based designs. The HCT series ensures compatibility with standard TTL inputs while offering lower power consumption than older LS families. Consider the three enable inputs for complex address decoding scenarios where multiple devices must be cascaded or controlled simultaneously without additional logic gates.

Part Context

This device belongs to the SNx4HCT138 family of 3-line to 8-line decoders and demultiplexers. It is part of Texas Instruments' broader portfolio of logic ICs designed for digital signal processing and memory interfacing. The 'HCT' designation indicates High-Speed CMOS technology with TTL-compatible inputs, bridging the gap between legacy TTL systems and modern CMOS architectures.

Replacement Considerations

SN74HCT138DR

FAQ

How many enable inputs does the SN74HCT138DRG4 have?

The device incorporates three enable inputs: two active-low (G2A and G2B) and one active-high (G1).

What is the typical propagation delay of this decoder?

The typical propagation delay (tpd) is 17 ns when operating at a supply voltage of 5 V.