Encyclopedia Entry: 74AC251SC

Product Overview

Category

The 74AC251SC belongs to the category of integrated circuits (ICs).

Use

This IC is commonly used in digital electronic circuits for data multiplexing and demultiplexing applications.

Characteristics

• The 74AC251SC is a quad 2-input multiplexer with three-state outputs.
• It operates on a supply voltage range of 2V to 6V, making it suitable for various digital systems.
• This IC offers high-speed operation and low power consumption.
• It has a wide operating temperature range, typically from -40°C to 85°C.

Package

The 74AC251SC is available in a small outline integrated circuit (SOIC) package.

Essence

The essence of the 74AC251SC lies in its ability to select one of four input data sources and route it to a single output line.

Packaging/Quantity

The 74AC251SC is typically packaged in reels or tubes, containing a quantity of 250 or 2,500 units per package.

Specifications

• Supply Voltage Range: 2V to 6V
• Operating Temperature Range: -40°C to 85°C
• Input Voltage High Level (VIH): 2V to VCC + 0.5V
• Input Voltage Low Level (VIL): -0.5V to 0.8V
• Output Voltage High Level (VOH): VCC - 0.1V
• Output Voltage Low Level (VOL): 0.1V
• Propagation Delay Time: 4.5ns (max)
• Power Dissipation: 25mW (typ)

Detailed Pin Configuration

The 74AC251SC has a total of 16 pins, each serving a specific function. The pin configuration is as follows:

1. A0: Input A0
2. B0: Input B0
3. I0: Input I0
4. I1: Input I1
5. Y: Output Y
6. G: Enable Input G
7. VCC: Positive Power Supply
8. GND: Ground
9. A1: Input A1
10. B1: Input B1
11. I2: Input I2
12. I3: Input I3
13. Y: Output Y
14. G: Enable Input G
15. A2: Input A2
16. B2: Input B2

Functional Features

The 74AC251SC offers the following functional features:

• Quad 2-input multiplexer with three-state outputs.
• Selects one of four input data sources based on control inputs.
• Enables or disables the output using the enable input (G).
• Provides high-speed operation and low power consumption.

Advantages and Disadvantages

Advantages

• High-speed operation allows for efficient data routing in digital circuits.
• Low power consumption helps conserve energy in electronic systems.
• Three-state outputs provide flexibility in connecting multiple devices.

Disadvantages

• Limited to a maximum supply voltage of 6V, which may restrict its use in certain applications.
• Propagation delay time may affect timing-sensitive circuits.

Working Principles

The 74AC251SC operates by selecting one of the four input data sources based on the control inputs (A0, A1, A2). The selected input is then routed to the output line (Y) when the enable input (G) is active. When the enable input is inactive, the output is in a high-impedance state, allowing other devices to drive the output line.

Detailed Application Field Plans

The 74AC251SC finds applications in various digital systems, including but not limited to:

1. Data multiplexing and demultiplexing in communication systems.
2. Address decoding in microprocessors and memory devices.
3. Input/output (I/O) expansion in embedded systems.
4. Signal routing in audio/video equipment.
5. Control signal selection in industrial automation.

Detailed and Complete Alternative Models

Some alternative models that offer similar functionality to the 74AC251SC include:

1. 74HC251: High-speed CMOS logic quad 2-input multiplexer.
2. CD4052: Dual 4-channel analog multiplexer/demultiplexer.
3. SN54LS157: Quad 2-line to 1-line data selectors/multiplexers.

These alternatives can be considered based on specific requirements and compatibility with the existing system.

In conclusion, the 74AC251SC is a versatile integrated circuit used for data multiplexing and demultiplexing applications. Its high-speed operation, low power consumption, and three-state outputs make it suitable for various digital systems. With its compact SOIC package, it offers