SCAS946B November   2016  – March 2025 CDCLVP111-SP

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
    1.     Pin 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 LVECL DC Electrical Characteristics
    6. 5.6 LVPECL DC Electrical Characteristics
    7. 5.7 AC Electrical Characteristics
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Fanout Buffer for Line Card Application
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1 LVPECL Output Termination
          2. 7.2.1.2.2 Input Termination
        3. 7.2.1.3 Application Curves
    3. 7.3 Power Supply Recommendations
      1. 7.3.1 Power-Supply Filtering
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      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

6.1 Overview

The CDCLVP111-SP is an open emitter for LVPECL outputs. Therefore, proper biasing and termination are required to provide correct operation of the device and to minimize signal integrity. The proper termination for LVPECL outputs is 50Ω to (VCC – 2), but this DC voltage is not readily available on PCB. Therefore, a Thevenin equivalent circuit is worked out for the LVPECL termination in both direct-coupled (DC) and AC-coupled configurations. These configurations are shown in Figure 7-2 (a and b) for VCC = 2.5V and Figure 7-3 (a and b) for VCC = 3.3V, respectively. TI recommends to place all resistive components close to either the driver end or the receiver end. If the supply voltage for the driver and receiver is different, AC coupling is required.