CD74HC138MT

Signal Switches, Multiplexers, Decoders Overview

The CD74HC138MT is a high-speed CMOS logic decoder and demultiplexer manufactured by Texas Instruments. It features a single 3-to-8 line decoding circuit housed in a 16-pin SOIC package. The device operates within a supply voltage range of 2V to 6V and supports an extended industrial temperature range from -55°C to +125°C. It includes three binary selection inputs and two active-low plus one active-high enable inputs to facilitate cascading. The outputs are low-active, capable of driving up to ten LSTTL loads, with typical propagation delays around 13ns at 5V.

Signal Switches, Multiplexers, Decoders Feature Summary

• High-speed silicon gate CMOS technology providing performance comparable to low-power Schottky TTL while maintaining low power consumption.
• Three binary selection inputs determine which of the eight normally high outputs goes low when enabled.
• Two active-low and one active-high enable inputs simplify cascading without requiring external inverters.

Signal Switches, Multiplexers, Decoders Applications

• Memory address decoding in high-performance storage systems
• Data routing applications requiring short propagation delay
• Industrial control systems operating in wide temperature ranges

Signal Switches, Multiplexers, Decoders Procurement Notes

Verify the specific suffix 'MT' against the official Texas Instruments datasheet for the CD74HC138 series to confirm the exact package type and tape-and-reel specifications. Ensure the component meets RoHS compliance requirements if applicable to your manufacturing process. Cross-reference the manufacturer part number with authorized distributors to confirm current availability and authenticity before procurement.

Signal Switches, Multiplexers, Decoders Selection Notes

Select this component when designing circuits that require fast decoding speeds combined with low power dissipation. It is suitable for replacing older TTL-based decoders in modern CMOS designs. Consider the extended temperature range (-55°C to +125°C) for harsh environments. Verify that the output drive capability meets the load requirements of the connected downstream logic gates.

Signal Switches, Multiplexers, Decoders Part Context

This component belongs to the HC (High-speed CMOS) logic family, designed to offer faster switching speeds than standard 74C series devices while consuming less power than 74LS series. The 138 variant specifically provides 3-to-8 decoding functionality. It is widely used in digital systems where memory mapping or data distribution is required. The device is compatible with other members of the 74HC and 74HCT families for system integration.

Signal Switches, Multiplexers, Decoders Replacement Considerations

Compatible substitutes include SN74HC138 variants from Texas Instruments and equivalent parts from other manufacturers such as NXP or onsemi, provided they match the 16-pin SOIC package and electrical characteristics. Ensure any replacement maintains the same enable logic polarity and output inversion state.