SGLS423B February   2025  – February 2026 SN55LVRA4-SEP

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 Receiver Output States
      2. 7.3.2 General Purpose Comparator
      3. 7.3.3 Common-Mode Range vs Supply Voltage
    4. 7.4 Equivalent Input and Output Schematic Diagrams
    5. 7.5 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Detailed Design Procedure
      2. 8.2.2 Design Requirements
      3. 8.2.3 Application Performance Plots
      4. 8.2.4 Cold Sparing
    3. 8.3 Active Failsafe Feature
    4. 8.4 ECL/PECL-to-LVTTL Conversion with TI's LVDS Receiver
    5. 8.5 Test Conditions
    6. 8.6 Equipment
  10. 9 Power Supply Recommendations
    1. 9.1 Supply Bypass Capacitance
  11. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Microstrip vs. Stripline Topologies
      2. 10.1.2 Dielectric Type and Board Construction
      3. 10.1.3 Recommended Stack Layout
      4. 10.1.4 Separation Between Traces
      5. 10.1.5 Crosstalk and Ground Bounce Minimization
    2. 10.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

10.1.3 Recommended Stack Layout

Following the choice of dielectrics and design specifications, the user should decide how many levels to use in the stack. To reduce the TTL/CMOS to LVDS crosstalk, a good practice is to have at least two separate signal planes as shown in Figure 10-3.

SN55LVRA4-SEP Four-Layer PCB BoardFigure 10-3 Four-Layer PCB Board
Note:

The separation between layers 2 and 3 should be 127μm (0.005in). By keeping the power and ground planes tightly coupled, the increased capacitance acts as a bypass for transients.

One of the most common stack configurations is the six-layer board, as shown in Figure 10-4.

SN55LVRA4-SEP Six-Layer PCB BoardFigure 10-4 Six-Layer PCB Board

In this particular configuration, it is possible to isolate each signal layer from the power plane by at least one ground plane. The result is improved signal integrity; however, fabrication is more expensive. Using the 6-layer board is preferable, because it offers the layout designer more flexibility in varying the distance between signal layers and referenced planes, in addition to ensuring reference to a ground plane for signal layers 1 and 6.