SNOSDC1A June   2024  – October 2024 LMH1229 , LMH1239

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 Electrical Characteristics
    6. 5.6 Timing Requirements for Serial Management (SM) Bus Interface
    7. 5.7 Timing Requirements for Serial Parallel Interface (SPI) Interface
    8. 5.8 Typical Characteristics
      1. 5.8.1 TX Characteristics
      2. 5.8.2 RX Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 4-Level Input Pins and Thresholds
      2. 6.3.2 Input and Output Signal Flow Control
        1. 6.3.2.1 Input Mux Selection (LMH1239 Only)
        2. 6.3.2.2 Output Mux and SDI_OUT Selection
      3. 6.3.3 Input Carrier Detect
      4. 6.3.4 Adaptive Cable Equalizer (SDI_IN±, SDI_IN1±)
      5. 6.3.5 Clock and Data (CDR) Recovery
      6. 6.3.6 CDR Loop Bandwidth Control
      7. 6.3.7 Output Function Control
      8. 6.3.8 Output Driver Control
        1. 6.3.8.1 Line-Side 75Ω Output Cable Driver (SDI_OUT±)
          1. 6.3.8.1.1 Output Amplitude (VOD)
          2. 6.3.8.1.2 Output Pre-Emphasis
          3. 6.3.8.1.3 Output Slew Rate
          4. 6.3.8.1.4 Output Polarity Inversion
        2. 6.3.8.2 Host-Side 100Ω Output Driver (OUT0±, OUT1±)
      9. 6.3.9 Debug and Diagnostic Features
        1. 6.3.9.1 Internal Eye Opening Monitor (EOM)
        2. 6.3.9.2 PRBS Generator, Error Checker, and Error Injector
        3. 6.3.9.3 Status Indicators and Interrupts
          1. 6.3.9.3.1 LOCK_N (Lock Indicator)
          2. 6.3.9.3.2 CD_N (Carrier Detect)
          3. 6.3.9.3.3 Cable Fault Detection (SDI_OUT+ Only)
          4. 6.3.9.3.4 INT_N (Interrupt)
        4. 6.3.9.4 Additional Programmability
          1. 6.3.9.4.1 Cable EQ Index (CEI)
          2. 6.3.9.4.2 Digital MUTEREF
    4. 6.4 Device Functional Modes
      1. 6.4.1 System Management Bus (SMBus) Mode
        1. 6.4.1.1 SMBus Read and Write Transaction
          1. 6.4.1.1.1 SMBus Write Operation Format
          2. 6.4.1.1.2 SMBus Read Operation Format
      2. 6.4.2 Serial Peripheral Interface (SPI) Mode
        1. 6.4.2.1 SPI Read and Write Transactions
          1. 6.4.2.1.1 SPI Write Transaction Format
          2. 6.4.2.1.2 SPI Read Transaction Format
        2. 6.4.2.2 SPI Daisy Chain
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 SMPTE Requirements and Specifications
      2. 7.1.2 Optimizing the Time to Adapt and Lock
      3. 7.1.3 Optimized Loop Bandwidth Settings for Diagnostic or Cascade Applications
      4. 7.1.4 LMH1229 and LMH1297 (EQ Mode) Pin-to-Pin Compatibility
    2. 7.2 Typical Application
      1. 7.2.1 Cable Equalizer With Loop-Through
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curves
      2. 7.2.2 Cable Equalizer With Redundant SDI Input (LMH1239 only)
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 Board Stack-Up and Ground References
        2. 7.4.1.2 High-Speed PCB Trace Routing and Coupling
          1. 7.4.1.2.1 SDI_IN± and SDI_OUT±:
          2. 7.4.1.2.2 OUT0± and OUT1±:
        3. 7.4.1.3 Anti-Pads
        4. 7.4.1.4 BNC Connector Layout and Routing
        5. 7.4.1.5 Power Supply and Ground Connections
        6. 7.4.1.6 Footprint Recommendations
      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

Package Options

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

6.3.6 CDR Loop Bandwidth Control

A key characteristic of CDR operation is the loop bandwidth. Input jitter at frequencies above the -3dB CDR loop bandwidth are attenuated by the CDR, while input jitter at frequencies below the -3dB CDR loop bandwidth are tracked but not attenuated at the CDR output. Depending on the input jitter present at the LMH12x9 input and application needs for the LMH12x9 output jitter, the CDR loop bandwidth can be adjusted.

The LMH12x9 features a highly configurable CDR loop bandwidth that can be controlled by either pin or register settings.

Note: The default LMH12x9 CDR loop bandwidth (no external capacitor on LF+ and LF- pins) are comparable to previous generation LMH1219 and LMH1297 (EQ Mode) devices. To enable a lower CDR loop bandwidth, an external 470nF capacitor on LF+ and LF- is required.