SCASE42 November   2024 SN74ACT139

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Switching Characteristics
    7. 5.7 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Balanced CMOS Push-Pull Outputs
      2. 7.3.2 TTL-Compatible CMOS Inputs
      3. 7.3.3 Clamp Diode Structure
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Power Considerations
        2. 8.2.1.2 Input Considerations
        3. 8.2.1.3 Output Considerations
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.1 Overview

The SN74ACT139 is a high speed silicon gate CMOS decoder well suited to memory address decoding or data routing applications. It contains two 2:4 decoders.

Each channel of the SN74ACT139 has two address select inputs (A and B). The circuit functions as a normal one-of-four decoder.

One strobe input (G) is provided for each channel to simplify cascading and to facilitate demultiplexing. When the input strobe for a channel is inactive, that channel's outputs are forced into the high state.

The demultiplexing function is accomplished by first using the select inputs to choose the desired output, and then using the strobe input as the data input. The data will appear non-inverted at the selected output.

The outputs for the SN74ACT139 are normally high, and low when selected.