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

6.4 Device Functional Modes

SPI register access is required while operating the LMH0387 in the input mode. Set the equalizer launch amplitude fine tuning to nominal through the SPI for correct equalizer operation. To do this, write 30h (“00110000 binary”) to SPI register 02h. The SPI registers provide access to many other useful LMH0387 features while in the input mode.

Enable the cable driver to configure the LMH0387 in the output mode. Disable the equalizer either for power savings or enable it to provide a loopback path for the data being transmitted. For the normal output mode (equalizer disabled for power savings) follow these steps:

  1. Disable the equalizer by forcing it to sleep through the SPI. To do this, write “10” (force sleep) to bits [4:3] of SPI register 00h.
  2. Enable the cable driver by pulling the TX_EN pin high.