CD74HCT138E-NG

Overview

The CD74HCT138E-NG is a high-speed CMOS logic decoder manufactured by Texas Instruments. It functions as a 3-to-8 line decoder/demultiplexer within the HCT logic family, designed for memory address decoding and data routing applications. The device features three binary select inputs that determine which of the eight outputs is activated. It operates with a supply voltage range of 4.5 V to 5.5 V and includes multiple enable inputs to facilitate cascading. The component is housed in a PDIP-16 package and supports through-hole mounting.

Feature Summary

• Provides three binary select inputs to decode signals into one of eight distinct output lines
• Features active-low outputs suitable for direct interfacing with TTL loads
• Includes dedicated enable inputs to simplify system expansion and cascading configurations

Applications

• Memory address decoding in computer systems
• Data routing and distribution networks
• I/O port selection circuits

Procurement Notes

Verify the specific suffix 'NG' against official Texas Instruments documentation to confirm exact packaging or material specifications. Ensure the ordering part number matches the required PDIP-16 through-hole configuration. Cross-reference datasheet parameters such as propagation delay and operating temperature range with your design requirements before finalizing procurement.

Selection Notes

Select this component when a 3-to-8 decoding function is required with HCT logic compatibility. It is appropriate for designs needing direct interface with LSTTL loads due to its input/output characteristics. Consider the PDIP-16 package if through-hole assembly is mandated by the PCB layout constraints.

Part Context

This part belongs to the Texas Instruments 74HCT series of high-speed CMOS logic devices. The series combines the low power consumption typical of CMOS technology with speed and input compatibility comparable to Low-Power Schottky TTL. These decoders are widely used in digital systems requiring reliable signal demultiplexing and address decoding.

Replacement Considerations

Compatible substitutes include the CD74HC138E and SN74HCT138PWR. Verify pinout compatibility and ensure voltage level matching between HC and HCT families.