CD74HCT138MTE4

Overview

The CD74HCT138MTE4 is a high-speed CMOS 3-to-8 line decoder/demultiplexer manufactured by Texas Instruments. It operates within a supply voltage range of 4.5 V to 5.5 V and features three binary address inputs (A0, A1, A2) that select one of eight outputs. The device includes two active-low enable inputs (E1, E2) and one active-high enable input (E3). Outputs are active low for the HC variant configuration. It is housed in a 16-pin SOIC package.

Feature Summary

• Provides decoding or demultiplexing functions with three binary address lines controlling eight distinct output channels.
• Incorporates dual active-low and single active-high enable inputs to facilitate cascading multiple units without external logic gates.
• Delivers high-speed performance comparable to Low-Power Schottky TTL while maintaining standard CMOS power consumption characteristics.

Applications

• Memory address decoding in computer systems
• Data routing and distribution networks
• Industrial control system signal selection

Procurement Notes

Verify the specific suffix 'E4' indicates lead-free composition and RoHS compliance as per manufacturer standards. Confirm the 'MT' designator corresponds to the specified tape-and-reel packaging format. Ensure the operating temperature range aligns with industrial requirements before finalizing procurement orders.

Selection Notes

Select this component when a 3-to-8 decoding function is required with CMOS compatibility. It serves as a direct replacement for legacy LS-TTL decoders where lower power dissipation is critical. Verify that the 4.5V minimum supply voltage meets the system's power rail specifications.

Part Context

This part belongs to the CD74HCT series of high-speed CMOS logic devices. It is functionally compatible with the SN74HCT138 family. The device is designed to interface directly with TTL logic circuits due to its input threshold levels, bridging the gap between older TTL systems and modern CMOS architectures.

Replacement Considerations

Direct pin-compatible substitutes include the SN74HCT138 and CD74HC138 variants. Verify that the alternative package type matches the PCB footprint constraints and that the enable logic polarity remains consistent with the existing circuit design.