Encyclopedia Entry: 74F257APC

Product Overview

Category

The 74F257APC belongs to the category of integrated circuits (ICs) and specifically falls under the family of multiplexers/demultiplexers.

Use

This IC is commonly used in digital electronics for data multiplexing and demultiplexing applications. It allows multiple input signals to be selected and routed to a single output or vice versa.

Characteristics

• The 74F257APC is a quad 2-input multiplexer with 3-state outputs.
• It operates on a supply voltage range of 4.5V to 5.5V.
• This IC offers high-speed operation, making it suitable for use in various digital systems.
• It features low power consumption, ensuring efficient energy usage.
• The 74F257APC is designed to provide reliable performance and has a wide operating temperature range.

Package and Quantity

The 74F257APC is available in a 16-pin plastic dual in-line package (PDIP). It is typically sold in reels or tubes containing multiple units, with quantities varying based on the supplier and customer requirements.

Specifications

• Supply Voltage Range: 4.5V to 5.5V
• Input Voltage High: 2.0V (min), 0.8V (max)
• Input Voltage Low: 0.8V (min), -0.5V (max)
• Output Voltage High: 2.7V (min), 2.4V (max)
• Output Voltage Low: 0.4V (min), 0.1V (max)
• Operating Temperature Range: -40°C to +85°C
• Propagation Delay Time: 6ns (typical)

Pin Configuration

The 74F257APC has a total of 16 pins, each serving a specific function. The pin configuration is as follows:

1. A0 (Input)
2. B0 (Input)
3. Y0 (Output)
4. G (Enable Input)
5. A1 (Input)
6. B1 (Input)
7. Y1 (Output)
8. VCC (Supply Voltage)
9. Y2 (Output)
10. B2 (Input)
11. A2 (Input)
12. Y3 (Output)
13. GND (Ground)
14. B3 (Input)
15. A3 (Input)
16. Y4 (Output)

Functional Features

The 74F257APC offers the following functional features:

• Quad 2-input multiplexer: It allows selection and routing of four different input signals to a single output based on the control inputs.
• 3-state outputs: The outputs can be put in a high-impedance state, enabling multiple devices to share a common bus without interference.
• Enable input (G): This input controls the operation of the multiplexer/demultiplexer, allowing it to be enabled or disabled as required.

Advantages and Disadvantages

Advantages

• High-speed operation enables efficient data processing in digital systems.
• Low power consumption contributes to energy efficiency.
• Reliable performance ensures stable operation in various applications.
• 3-state outputs facilitate bus sharing and reduce signal interference.

Disadvantages

• Limited number of input/output channels compared to larger multiplexer/demultiplexer ICs.
• Requires external control signals for proper operation.

Working Principles

The 74F257APC operates based on the principles of digital logic. It uses the control inputs (A0-A3) and enable input (G) to select one of the four input channels and route it to the corresponding output channel (Y0-Y4). The selected input is determined by the binary combination of the control inputs. When the enable input (G) is active, the output reflects the selected input; otherwise, the outputs are in a high-impedance state.

Application Field Plans

The 74F257APC finds applications in various digital systems and electronic devices, including but not limited to:

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

Alternative Models

For similar functionality and application requirements, alternative models to the 74F257APC include:

1. 74HC257: A CMOS-based quad 2-input multiplexer with 3-state outputs.
2. CD4051: An analog multiplexer/demultiplexer IC with 8 channels.
3. SN74LS151: A TTL-based 8-input multiplexer with 3-state outputs.

These alternative models offer comparable features and can be considered based on specific design considerations and