MC74HCT138AN

Product Overview

• Category: Integrated Circuit
• Use: Decoding and Demultiplexing
• Characteristics: High-Speed CMOS Logic, 3-to-8 Line Decoder/Demultiplexer
• Package: DIP (Dual In-line Package)
• Essence: The MC74HCT138AN is a decoder/demultiplexer IC that converts a binary input into a corresponding output line.
• Packaging/Quantity: Available in tubes or reels, with varying quantities depending on the supplier.

Specifications

The MC74HCT138AN has the following specifications:

• Supply Voltage: 2V to 6V
• Input Voltage: 0V to VCC
• Output Voltage: 0V to VCC
• Maximum Operating Frequency: 25 MHz
• Number of Inputs: 3
• Number of Outputs: 8
• Propagation Delay: 15 ns (typical)

Detailed Pin Configuration

The MC74HCT138AN has a total of 16 pins. Here is the detailed pin configuration:

1. GND (Ground)
2. A2 (Input A2)
3. A1 (Input A1)
4. A0 (Input A0)
5. E1 (Enable Input 1)
6. Y0 (Output Y0)
7. Y1 (Output Y1)
8. Y2 (Output Y2)
9. Y3 (Output Y3)
10. Y4 (Output Y4)
11. Y5 (Output Y5)
12. Y6 (Output Y6)
13. Y7 (Output Y7)
14. E2 (Enable Input 2)
15. VCC (Positive Power Supply)
16. GND (Ground)

Functional Features

The MC74HCT138AN offers the following functional features:

• Decodes a 3-bit binary input into one of eight output lines.
• Demultiplexes the selected output line based on the input configuration.
• High-speed operation with CMOS logic.
• Low power consumption.
• Schmitt-trigger inputs for noise immunity.

Advantages and Disadvantages

Advantages of the MC74HCT138AN include:

• Fast decoding and demultiplexing capability.
• Wide operating voltage range.
• Low power consumption.
• Noise immunity due to Schmitt-trigger inputs.

Disadvantages of the MC74HCT138AN include:

• Limited number of input bits (3 bits).
• Propagation delay may affect timing-sensitive applications.
• Requires external enable inputs for proper operation.

Working Principles

The MC74HCT138AN works by accepting a 3-bit binary input and converting it into one of eight possible output lines. The input bits A2, A1, and A0 determine which output line is active. The enable inputs E1 and E2 control the overall operation of the decoder/demultiplexer.

When the enable inputs are active, the selected output line becomes active and outputs a high signal. All other output lines remain inactive and output a low signal. The MC74HCT138AN operates at high speed and consumes low power due to its CMOS logic design.

Detailed Application Field Plans

The MC74HCT138AN can be used in various applications, including:

1. Address decoding in microcontrollers and microprocessors.
2. Memory selection in digital systems.
3. Data routing and selection in multiplexers.
4. Signal demultiplexing in communication systems.
5. Control signal generation in industrial automation.

Detailed and Complete Alternative Models

Some alternative models to the MC74HCT138AN include:

1. 74HC138: Similar functionality but operates at a higher voltage range.
2. CD74HCT138: Equivalent functionality but available in different package options.
3. SN74HCT138: Similar functionality but with improved noise immunity.

These alternative models can be considered based on specific requirements and availability.

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