Encyclopedia Entry: 74AC646SC

Product Overview

Category

The 74AC646SC belongs to the category of integrated circuits (ICs) and specifically falls under the family of digital logic devices.

Use

This product is primarily used for data bus transceiver applications in various electronic systems. It enables bidirectional data transfer between two buses with different voltage levels.

Characteristics

• Voltage Compatibility: The 74AC646SC is designed to operate with a wide range of supply voltages, typically ranging from 2V to 6V.
• High-Speed Operation: It offers fast switching speeds, making it suitable for high-performance applications.
• Bidirectional Data Transfer: This IC facilitates data transmission in both directions, allowing seamless communication between two buses.
• Output Enable Control: The device features an output enable pin that can be used to disable the outputs when not required.

Package and Quantity

The 74AC646SC is available in a small outline package (SOIC) with 20 pins. It is commonly sold in reels or tubes containing multiple units, with quantities varying based on the supplier.

Specifications

• Supply Voltage Range: 2V to 6V
• Input Voltage Range: 0V to VCC
• Operating Temperature Range: -40°C to +85°C
• Maximum Propagation Delay: 8 ns
• Maximum Output Current: ±24 mA

Pin Configuration

The 74AC646SC has a total of 20 pins, each serving a specific function. The detailed pin configuration is as follows:

1. OE (Output Enable)
2. A0 (Data Bus A, Bit 0)
3. A1 (Data Bus A, Bit 1)
4. A2 (Data Bus A, Bit 2)
5. A3 (Data Bus A, Bit 3)
6. A4 (Data Bus A, Bit 4)
7. A5 (Data Bus A, Bit 5)
8. GND (Ground)
9. B5 (Data Bus B, Bit 5)
10. B4 (Data Bus B, Bit 4)
11. B3 (Data Bus B, Bit 3)
12. B2 (Data Bus B, Bit 2)
13. B1 (Data Bus B, Bit 1)
14. B0 (Data Bus B, Bit 0)
15. DIR (Direction Control)
16. VCC (Supply Voltage)
17. BDIR (Bus Direction Control)
18. OE2 (Output Enable 2)
19. OEA (Output Enable A)
20. OEB (Output Enable B)

Functional Features

The 74AC646SC offers the following functional features:

• Bidirectional Data Transfer: It allows data to be transmitted bidirectionally between two buses.
• Direction Control: The DIR and BDIR pins control the direction of data flow.
• Output Enable Control: The OE, OE2, OEA, and OEB pins enable or disable the outputs as required.

Advantages and Disadvantages

Advantages

• Wide voltage compatibility range allows for versatile use in different systems.
• High-speed operation enables efficient data transfer.
• Bidirectional functionality simplifies bus communication.
• Output enable control provides flexibility in managing output states.

Disadvantages

• Limited number of data bits (6 bits per bus) may restrict its applicability in certain scenarios.
• Requires careful consideration of voltage levels to ensure proper operation.

Working Principles

The 74AC646SC operates based on a combination of digital logic circuits and transceiver principles. It utilizes internal circuitry to facilitate bidirectional data transfer between two buses while maintaining compatibility with different voltage levels. The direction of data flow is controlled by the DIR and BDIR pins, and the outputs can be enabled or disabled using the OE, OE2, OEA, and OEB pins.

Application Field Plans

The 74AC646SC finds applications in various electronic systems that require bidirectional data transfer between buses with different voltage levels. Some potential application fields include:

1. Microcontroller Interfacing: It can be used to interface microcontrollers with external devices operating at different voltage levels.
2. Communication Systems: The IC can facilitate data exchange between different communication protocols or interfaces.
3. Industrial Automation: It can be employed in industrial automation systems for data transmission between control units and peripheral devices.

Alternative Models

For users seeking alternatives to the 74AC646SC, several similar ICs are available in the market. Some notable alternatives include:

1. SN74LVC646A: This IC offers similar functionality with a lower supply voltage range.
2. CD74HCT646E: It provides compatibility with higher voltage levels while maintaining bidirectional data transfer capabilities.
3. MC74VHC646DW: This alternative offers improved speed performance compared to the 74AC646SC.

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