SCAS514H June   1995  – March 2024 SN54AC244 , SN74AC244

PRODMIX  

  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 Recommended Operating Conditions
    3. 5.3 Thermal Information
    4. 5.4 Electrical Characteristics
    5. 5.5 Switching Characteristics, VCC = 3.3 V ± 0.3 V
    6. 5.6 Switching Characteristics, VCC = 5 V ± 0.5 V
    7. 5.7 Operating Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Power Supply Recommendations
    2. 8.2 Layout
      1. 8.2.1 Layout Guidelines
        1. 8.2.1.1 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DB|20
  • RKS|20
  • NS|20
  • N|20
  • DGS|20
  • DW|20
  • PW|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.1 Layout Guidelines

Reflections and matching are closely related to the loop antenna theory but are different enough to be discussed separately from the theory. When a PCB trace turns a corner at a 90° angle, a reflection can occur. A reflection occurs primarily because of the change of width of the trace. At the apex of the turn, the trace width increases to 1.414 times the width. This increase upsets the transmission-line characteristics, especially the distributed capacitance and self-inductance of the trace, which results in the reflection. Not all PCB traces can be straight; therefore, some traces must turn corners. Layout example for SNx4AC244 shows progressively better techniques of rounding corners. Only the last example (BEST) maintains constant trace width and minimizes reflections.