MC74AC138DTR2

Product Overview

• Category: Integrated Circuit (IC)
• Use: Decoder/Demultiplexer
• Characteristics: High-speed, low-power, 3-to-8 line decoder/demultiplexer
• Package: SOIC-16
• Essence: Converts a binary input into a corresponding output based on the selected line
• Packaging/Quantity: Tape and Reel, 2500 units per reel

Specifications

• Logic Family: AC
• Number of Inputs: 3
• Number of Outputs: 8
• Supply Voltage: 2V to 6V
• Operating Temperature Range: -40°C to +85°C
• Propagation Delay: 5 ns (typical)
• Output Current: ±24 mA
• Input Capacitance: 3 pF (typical)

Detailed Pin Configuration

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

Functional Features

• Decodes a 3-bit binary input into one of eight outputs
• Enables individual outputs using enable inputs
• High-speed operation with low power consumption
• Compatible with TTL and CMOS logic levels
• Schmitt trigger inputs for noise immunity

Advantages and Disadvantages

Advantages

• High-speed operation allows for quick decoding of input signals
• Low power consumption makes it suitable for battery-powered devices
• Schmitt trigger inputs provide improved noise immunity
• Wide operating voltage range enhances versatility

Disadvantages

• Limited to 3-bit binary inputs, restricting the number of possible combinations
• Output current limitations may restrict use in certain applications requiring higher currents

Working Principles

The MC74AC138DTR2 is a decoder/demultiplexer IC that converts a 3-bit binary input into one of eight corresponding outputs. The input lines (A0, A1, and A2) determine which output line (Y0 to Y7) will be active. The enable inputs (E1 and E2) control the activation of specific output lines.

When the enable inputs are low, the outputs are disabled regardless of the input values. When the enable inputs are high, the selected output line becomes active based on the binary input. The remaining output lines remain inactive.

The IC operates at high speed with low power consumption, making it suitable for various applications where decoding and demultiplexing functions are required.

Detailed Application Field Plans

The MC74AC138DTR2 finds applications in various fields, including:

1. Address Decoding: Used in microcontrollers and memory systems to decode address signals and select specific memory locations.
2. Data Demultiplexing: Enables the distribution of data from a single source to multiple destinations, such as in communication systems or data routing.
3. Control Signal Decoding: Decodes control signals to activate specific functions or devices in industrial automation systems.
4. Display Multiplexing: Facilitates the multiplexing of display segments in digital displays, such as seven-segment displays or dot matrix displays.
5. Programmable Logic Devices: Utilized in programmable logic devices to decode input signals and configure the device's internal logic.

Detailed and Complete Alternative Models

1. 74HC138: Similar 3-to-8 line decoder/demultiplexer with slightly different electrical characteristics.
2. CD74AC138: Another alternative with AC characteristics, but available in a different package (PDIP-16).
3. SN74LS138: A TTL-compatible alternative with similar functionality but different voltage levels and propagation delay.

These alternative models provide similar decoding and demultiplexing capabilities, allowing users to choose the most suitable option based on their specific requirements.

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