SNLS590C August   2018  – June 2021 DS250DF230

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Device Data Path Operation
      2. 8.3.2  Signal Detect
      3. 8.3.3  Continuous Time Linear Equalizer (CTLE)
      4. 8.3.4  Variable Gain Amplifier (VGA)
      5. 8.3.5  Cross-Point Switch
      6. 8.3.6  Decision Feedback Equalizer (DFE)
      7. 8.3.7  Clock and Data Recovery (CDR)
        1. 8.3.7.1 CDR Bypass (Raw) Mode
        2. 8.3.7.2 CDR Fast Lock Mode
      8. 8.3.8  Calibration Clock
      9. 8.3.9  Differential Driver With FIR Filter
        1. 8.3.9.1 Setting the Output VOD, Pre-Cursor, and Post-Cursor Equalization
        2. 8.3.9.2 Output Driver Polarity Inversion
        3. 8.3.9.3 Slow Slew Rate
      10. 8.3.10 Debug Features
        1. 8.3.10.1 Pattern Generator
        2. 8.3.10.2 Pattern Checker
        3. 8.3.10.3 Eye-Opening Monitor
      11. 8.3.11 Interrupt Signals
    4. 8.4 Device Functional Modes
      1. 8.4.1 Supported Data Rates
      2. 8.4.2 SMBus Master Mode
      3. 8.4.3 Device SMBus Address
    5. 8.5 Programming
      1. 8.5.1 Bit Fields in the Register Set
      2. 8.5.2 Writing to and Reading from the Global/Shared/Channel Registers
    6. 8.6 Register Maps
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Front-Port Jitter Cleaning Applications
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Active Cable Applications
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
      3. 9.2.3 Backplane and Mid-Plane Applications
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
  13. 13Electrostatic Discharge Caution
  14. 14Glossary
  15. 15Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.3 Continuous Time Linear Equalizer (CTLE)

The CTLE in the DS250DF230 is a fully-adaptive equalizer. The CTLE adapts according to a Figure of Merit (FOM) calculation during the lock acquisition process. The FOM calculation is based upon the horizontal eye opening (HEO) and vertical eye opening (VEO). Once the CDR locks and the CTLE adapts, the CTLE boost level is frozen until a manual re-adapt command is issued or until the CDR re-enters the lock acquisition state. The CTLE can be re-adapted by resetting the CDR.

The CTLE consists of 4 stages, with each stage having 2-bit boost control. This allows for many boost combinations, including bypassing the first three stages EQs. The CTLE adaption algorithm allows the CTLE to adapt through 20 of these boost combinations. These 20 boost combinations comprise the EQ Table in the channel registers. See channel registers 0x40 through 0x53.

The boost levels can be set between approximately 0 dB and 25 dB (at 12.89 GHz.)