SCAS946A November   2016  – January 2017 CDCLVP111-SP

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 LVECL DC Electrical Characteristics
    6. 6.6 LVPECL DC Electrical Characteristics
    7. 6.7 AC Electrical Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Fanout Buffer for Line Card Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 LVPECL Output Termination
          2. 8.2.1.2.2 Input Termination
        3. 8.2.1.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Power-Supply Filtering
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • HFG|36
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Detailed Description

7.1 Overview

The CDCLVP111-SP is an open emitter for LVPECL outputs. Therefore, proper biasing and termination are required to ensure correct operation of the device and to minimize signal integrity. The proper termination for LVPECL outputs is 50 Ω 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 6 (a and b) for VCC = 2.5 V and Figure 7 (a and b) for VCC = 3.3 V, 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.

7.2 Functional Block Diagram

CDCLVP111-SP bd_cas859.gif

7.3 Feature Description

The CDCLVP111-SP is a low-additive jitter universal to LVPECL fan out buffer with 2 selectable inputs. The small package, low-output skew, and low-additive jitter make for a flexible device in demanding applications.

7.4 Device Functional Modes

Select input terminal by CLK_SEL pin.

Table 1. Function Table

CLK_SEL ACTIVE CLOCK INPUT
0 CLK0, CLK0
1 CLK1, CLK1

The two inputs of the CDCLVP111-SP are internally mixed together and can be selected through the control pin. Unused inputs and outputs can be left floating to reduce overall component cost. Both AC and DC coupling schemes can be used with the CDCLVP111-SP to provide greater system flexibility.