MC74HCT138ADR2G 3-to-8 Line Decoder/Demultiplexer – SOIC-16

Description

The MC74HCT138ADR2G is a high-speed CMOS 1-of-8 decoder/demultiplexer designed for applications requiring high-density address decoding or data routing. By utilizing LSTTL-compatible inputs, this device seamlessly bridges the gap between TTL logic families and high-performance CMOS systems. It is engineered to perform the task of decoding a 3-bit binary input into one of eight mutually exclusive active-LOW outputs.

The IC features three enable inputs—two active-LOW ($G_{2A}$, $G_{2B}$) and one active-HIGH ($G_1$)—which provide significant flexibility for cascading multiple decoders to expand the addressable range without the need for additional external gates. Its robust architecture ensures it remains a staple for memory mapping and peripheral selection in microprocessor systems.

Note: Product images are for illustrative purposes only. Because this device is designed for high-speed signal routing, please refer to the official ON Semiconductor datasheet for propagation delay timings and output drive characteristics to ensure optimal signal integrity on your PCB.

Features

• 1-of-8 Decoding: Converts 3 binary inputs into 8 independent, active-LOW output signals.
• LSTTL Compatible: Inputs are threshold-compatible with Low-Power Schottky TTL logic.
• Flexible Enable Logic: Three enable inputs ($G_1$, $G_{2A}$, $G_{2B}$) allow for easy cascading and expansion.
• High Speed: CMOS technology provides performance speeds comparable to LSTTL while maintaining lower power consumption.
• Robust Protection: Internal circuitry provides protection against electrostatic discharge (ESD).
• Package: SOIC-16 surface-mount (SMD) package for high-density applications.

Benefits

• Design Efficiency: Enables complex memory mapping and chip selection with a single, highly integrated component.
• Scalability: The multi-enable input structure makes it trivial to daisy-chain devices to create larger decoders.
• Reliability: Proven ON Semiconductor manufacturing ensures high reliability in demanding control environments.

Applications

• Memory Bank Selection: Decoding address lines to enable specific memory chips.
• Peripheral Addressing: Selecting I/O ports or registers in an embedded system.
• Data Demultiplexing: Routing a single data stream to one of eight different destination pathways.
• Sequential Control: Used in state machines to activate specific logic paths based on binary input.

Package Includes

• 1 x MC74HCT138ADR2G 1-of-8 Decoder/Demultiplexer IC (SMD-16)

Specifications