Encyclopedia Entry: 74AC251SCX

Product Overview

Category

The 74AC251SCX belongs to the category of integrated circuits (ICs).

Use

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

Characteristics

• The 74AC251SCX is a quad 2-input multiplexer with 3-state outputs.
• It operates on a supply voltage range of 2V to 6V, making it suitable for various electronic systems.
• This IC offers high-speed operation and low power consumption.
• It features Schottky-clamped inputs for improved noise immunity.
• The 74AC251SCX has 3-state outputs, allowing multiple devices to be connected together without bus contention issues.

Package and Quantity

The 74AC251SCX is available in a small outline package (SOIC) with 16 pins. It is typically sold in reels or tubes containing multiple units.

Specifications

• Supply Voltage Range: 2V to 6V
• Input Voltage High (VIH): 2V to VCC + 0.5V
• Input Voltage Low (VIL): -0.5V to 0.8V
• Output Voltage High (VOH): VCC - 0.1V
• Output Voltage Low (VOL): 0.1V
• Operating Temperature Range: -40°C to 85°C

Detailed Pin Configuration

The 74AC251SCX has 16 pins, each serving a specific function:

1. A0: Input A0
2. B0: Input B0
3. S: Select Input
4. GND: Ground
5. Y0: Output Y0
6. Y1: Output Y1
7. Y2: Output Y2
8. Y3: Output Y3
9. VCC: Supply Voltage
10. A1: Input A1
11. B1: Input B1
12. OE: Output Enable
13. Y4: Output Y4
14. Y5: Output Y5
15. Y6: Output Y6
16. Y7: Output Y7

Functional Features

The 74AC251SCX offers the following functional features:

• Quad 2-input multiplexer: It can select one of four input signals (A0, A1, B0, B1) based on the select input (S).
• 3-state outputs: The outputs (Y0 to Y7) can be put in a high-impedance state using the output enable (OE) pin.
• Schottky-clamped inputs: This feature enhances noise immunity and reduces signal distortion.

Advantages and Disadvantages

Advantages

• High-speed operation: The 74AC251SCX provides fast switching times, making it suitable for time-critical applications.
• Low power consumption: It consumes minimal power, contributing to energy-efficient designs.
• Noise immunity: The Schottky-clamped inputs improve the IC's ability to withstand external noise.

Disadvantages

• Limited input/output options: The IC only supports quad 2-input multiplexing, which may not be sufficient for complex systems requiring more inputs/outputs.
• Temperature limitations: The operating temperature range (-40°C to 85°C) may restrict its use in extreme environments.

Working Principles

The 74AC251SCX operates by selecting one of the four input signals (A0, A1, B0, B1) based on the select input (S). The selected input is then routed to the corresponding output (Y0 to Y7). The output enable (OE) pin allows the outputs to be put in a high-impedance state when necessary.

Detailed Application Field Plans

The 74AC251SCX finds applications in various digital electronic systems, including but not limited to:

1. Data multiplexing: It can be used to combine multiple data signals into a single output.
2. Data demultiplexing: It enables the separation of a single input signal into multiple outputs.
3. Address decoding: The IC can assist in selecting specific memory locations based on address inputs.

Alternative Models

For users seeking alternative options, the following integrated circuits can serve similar functions as the 74AC251SCX:

1. 74HC251: This IC offers similar functionality but operates at a lower voltage range (2V to 6V).
2. CD4051: It is an analog multiplexer/demultiplexer IC that can handle both digital and analog signals.
3. SN74LS151: This IC provides 8-input multiplexing capabilities, suitable for more complex systems.

In conclusion, the 74AC251SCX is a versatile quad 2-input multiplexer