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

6.3.1 4-Level Input Pins and Thresholds

The 4-level input configuration pins use a resistor divider to provide four logic states for each control pin. There is an internal 30kΩ pullup and a 60kΩ pulldown connected to the control pin that sets the default voltage at 2/3 x VIN. These resistors, together with the external resistor, combine to achieve the desired voltage level. By using the 1kΩ pulldown, 20kΩ pulldown, no connect, and 1kΩ pullup, the optimal voltage levels for each of the four input states are achieved as provided in Table 6-1.

Table 6-1 4-Level Control Pin Settings
LEVELSETTINGRESULTING PIN VOLTAGE
HTie 1 kΩ to VINVIN
FFloat (leave pin open)2/3 × VIN
RTie 20 kΩ to VSS1/3 × VIN
LTie 1 kΩ to VSS0

Typical 4-Level Input Thresholds:

  • Internal Threshold between L and R = 0.2 × VIN
  • Internal Threshold between R and F = 0.5 × VIN
  • Internal Threshold between F and H = 0.8 × VIN