ON Semiconductor
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DM74LS245WM
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DM74LS245WM

Overview

  • Category: Integrated Circuit
  • Use: Data Bus Transceiver
  • Characteristics:
    • High-speed operation
    • Wide voltage range
    • Bidirectional data transfer
    • TTL compatible inputs and outputs
  • Package: 20-pin SOIC (Small Outline Integrated Circuit)
  • Essence: Transceiver IC for bidirectional data communication
  • Packaging/Quantity: Available in reels of 2500 units

Specifications

  • Supply Voltage Range: 4.75V to 5.25V
  • Input Voltage Range: 0V to VCC
  • Output Voltage Range: 0V to VCC
  • Operating Temperature Range: -40°C to +85°C
  • Maximum Propagation Delay: 12ns
  • Maximum Output Current: ±15mA
  • Maximum Quiescent Power Dissipation: 500mW

Pin Configuration

The DM74LS245WM has a total of 20 pins, which are assigned as follows:

  1. A1 (Input A1)
  2. B1 (Input B1)
  3. GND (Ground)
  4. A2 (Input A2)
  5. B2 (Input B2)
  6. DIR (Direction Control)
  7. OE (Output Enable)
  8. Y1 (Output Y1)
  9. Y2 (Output Y2)
  10. GND (Ground)
  11. Y3 (Output Y3)
  12. Y4 (Output Y4)
  13. VCC (Supply Voltage)
  14. B4 (Input B4)
  15. A4 (Input A4)
  16. B3 (Input B3)
  17. A3 (Input A3)
  18. GND (Ground)
  19. B6 (Input B6)
  20. A6 (Input A6)

Functional Features

  • Bidirectional Data Transfer: The DM74LS245WM allows data to be transferred bidirectionally between two buses.
  • Direction Control (DIR): The DIR pin determines the direction of data flow.
  • Output Enable (OE): The OE pin enables or disables the outputs.
  • TTL Compatible Inputs and Outputs: The IC is compatible with TTL logic levels, making it easy to interface with other TTL devices.

Advantages and Disadvantages

Advantages: - High-speed operation allows for efficient data transfer. - Wide voltage range makes it suitable for various applications. - Bidirectional data transfer simplifies circuit design. - TTL compatibility ensures easy integration with other TTL devices.

Disadvantages: - Limited number of input/output pins restricts the number of data lines that can be transferred simultaneously. - Requires external control signals for proper operation.

Working Principles

The DM74LS245WM is a bidirectional data bus transceiver that facilitates communication between two separate data buses. The direction of data flow is determined by the DIR pin. When DIR is set to logic high, data is transferred from Bus A to Bus B, and when DIR is set to logic low, data flows from Bus B to Bus A. The OE pin is used to enable or disable the outputs. When OE is high, the outputs are enabled, allowing data to be transmitted. Conversely, when OE is low, the outputs are disabled, isolating the IC from the buses.

Detailed Application Field Plans

The DM74LS245WM is commonly used in various applications that require bidirectional data transfer, such as:

  1. Microprocessor Systems: It enables communication between the microprocessor and peripheral devices.
  2. Memory Interfaces: It facilitates data transfer between memory modules and the memory controller.
  3. Communication Systems: It is used in data transmission circuits for reliable and efficient communication.
  4. Industrial Automation: It plays a crucial role in connecting different components of automated systems.
  5. Automotive Electronics: It is utilized in automotive communication networks for data exchange.

Detailed and Complete Alternative Models

  1. SN74LS245: Similar to DM74LS245WM, but available in a different package (DIP-20).
  2. 74HC245: CMOS-based alternative with similar functionality and pin configuration.
  3. CD74HCT245: High-speed CMOS alternative with TTL compatibility.

These alternative models offer similar features and can be used as replacements for the DM74LS245WM depending on specific requirements.

In conclusion, the DM74LS245WM is a versatile integrated circuit that serves as a bidirectional data bus transceiver. Its high-speed operation, wide voltage range, and TTL compatibility make it suitable for various applications in microprocessor systems, memory interfaces, communication systems, industrial automation, and automotive electronics. While it has limitations in terms of the number of data lines and external control signals required, there are alternative models available to suit different needs.

Seznam 10 běžných otázek a odpovědí souvisejících s aplikací DM74LS245WM v technických řešeních

Sure! Here are 10 common questions and answers related to the application of DM74LS245WM in technical solutions:

  1. Q: What is DM74LS245WM? A: DM74LS245WM is a popular octal bus transceiver with tri-state outputs, commonly used for bidirectional data transfer between different voltage levels.

  2. Q: What is the maximum operating voltage for DM74LS245WM? A: The maximum operating voltage for DM74LS245WM is typically 5.25V.

  3. Q: Can DM74LS245WM be used for level shifting between different voltage domains? A: Yes, DM74LS245WM can be used for level shifting between different voltage domains as it supports bidirectional data transfer.

  4. Q: How many data lines can DM74LS245WM handle? A: DM74LS245WM can handle up to 8 data lines, making it suitable for applications requiring parallel data transfer.

  5. Q: Does DM74LS245WM have any built-in protection features? A: No, DM74LS245WM does not have built-in protection features. External measures should be taken to protect against voltage spikes or ESD events.

  6. Q: Can DM74LS245WM be used in high-speed applications? A: DM74LS245WM is not specifically designed for high-speed applications. It has a typical propagation delay of around 15-20 ns.

  7. Q: Is DM74LS245WM compatible with TTL logic levels? A: Yes, DM74LS245WM is compatible with TTL logic levels, making it suitable for interfacing with TTL-based devices.

  8. Q: Can DM74LS245WM be used in both input and output modes simultaneously? A: No, DM74LS245WM operates in either input or output mode at a given time. It cannot be used for bidirectional data transfer on the same line simultaneously.

  9. Q: What is the maximum current that DM74LS245WM can sink/source? A: DM74LS245WM can typically sink/source up to 24 mA of current per output pin.

  10. Q: Are there any specific precautions to consider when using DM74LS245WM? A: Yes, it is important to ensure proper decoupling and bypass capacitors are used near the power supply pins to minimize noise and voltage fluctuations. Additionally, care should be taken to avoid exceeding the maximum operating voltage or current limits specified in the datasheet.