SCAS551F November   1995  – February 2024 SN74AC564

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Description
  4. 3 Pin Configuration and Functions
  5. 4 Specifications
    1. 4.1 Absolute Maximum Ratings
    2. 4.2 Recommended Operating Conditions
    3. 4.3 Thermal Information
    4. 4.4 Electrical Characteristics
    5. 4.5 Timing Requirements, VCC = 3.3 V ± 0.3 V
    6. 4.6 Timing Requirements, VCC = 5 V ± 0.5 V
    7. 4.7 Switching Characteristics, VCC = 3.3 V ± 0.3 V
    8. 4.8 Switching Characteristics, VCC = 5 V ± 0.5 V
    9. 4.9 Operating Characteristics
  6. 5 Parameter Measurement Information
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Power Supply Recommendations
    2. 7.2 Layout
      1. 7.2.1 Layout Guidelines
      2. 7.2.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support (Analog)
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

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

7.2.1 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 the SN74AC564 shows progressively better techniques of rounding corners. Only the last example (BEST) maintains constant trace width and minimizes reflections.