SNLS315I April   2010  – June 2026 LMH0387

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  Control Pin Electrical Characteristics
    6. 5.6  Input Mode (Equalizer) DC Electrical Characteristics
    7. 5.7  Output Mode (Cable Driver) DC Electrical Characteristics
    8. 5.8  Input Mode (Equalizer) AC Electrical Characteristics
    9. 5.9  Output Mode (Cable Driver) AC Electrical Characteristics
    10. 5.10 Input Mode (Equalizer) SPI Interface AC Electrical Characteristics
    11. 5.11 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Input Mode (Equalizer) Description
        1. 6.3.1.1 Input Interfacing
        2. 6.3.1.2 Output Interfacing
        3. 6.3.1.3 Carrier Detect (CD)
        4. 6.3.1.4 Carrier Detect Threshold (CDTHRESH)
        5. 6.3.1.5 Auto Sleep
      2. 6.3.2 Output Mode (Cable Driver) Description
        1. 6.3.2.1 Input Interfacing
        2. 6.3.2.2 Output Interfacing
        3. 6.3.2.3 Output Slew Rate Control
        4. 6.3.2.4 Output Enable
    4. 6.4 Device Functional Modes
    5. 6.5 Programming
      1. 6.5.1 Output Mode (Cable Driver)
      2. 6.5.2 Input Mode (Equalizer)
      3. 6.5.3 Input Mode (Equalizer) SPI Register Access
        1. 6.5.3.1 SPI Write
        2. 6.5.3.2 SPI Read
        3. 6.5.3.3 Output Driver Adjustments (Register 01h)
          1. 6.5.3.3.1 Output Swing
          2. 6.5.3.3.2 Offset Voltage
        4. 6.5.3.4 Launch Amplitude Optimization (Register 02h)
          1. 6.5.3.4.1 Coarse Control
          2. 6.5.3.4.2 Fine Control
        5. 6.5.3.5 Cable Length Indicator (CLI) (Register 03h)
      4. 6.5.4 Input Mode (Equalizer) SPI Register Access
        1. 6.5.4.1 General Control (Register 00h)
          1. 6.5.4.1.1 Carrier Detect
          2. 6.5.4.1.2 Mute
          3. 6.5.4.1.3 Sleep Mode
          4. 6.5.4.1.4 Extended 3G Reach Mode
  8. 7 Register Maps
    1. 7.1 SPI Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 General Guidance for Applications
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

6.5.3.5 Cable Length Indicator (CLI) (Register 03h)

The Cable Length Indicator (CLI) provides an indication of the length of cable attached to the equalizer input. CLI is accessible through bits [7:3] of SPI register 03h. The 5-bit CLI ranges in decimal value from 0 to 25 (“00000” to “11001” binary) and increases as the cable length is increased. Figure 6-2 shows typical CLI values vs. Belden 1694A cable length. CLI is valid for Belden 1694A cable lengths from 0m to 120m at 2.97Gbps, 0m to 200m at 1.485Gbps, and 0m to 400m at 270Mbps.

LMH0387 CLI vs. Belden 1694A Cable Length Figure 6-2 CLI vs. Belden 1694A Cable Length