SNLS569C March   2017  – May 2020 LMH1208

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Block Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Recommended SMBus Interface Timing Specifications
    7. 6.7 Serial Parallel Interface (SPI) Timing Specifications
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 4-Level Input Pins and Thresholds
      2. 7.3.2 OUT0_SEL and SDI_OUT2_SEL Control
      3. 7.3.3 Input Signal Detect
      4. 7.3.4 Continuous Time Linear Equalizer (CTLE)
      5. 7.3.5 Output Driver Control
        1. 7.3.5.1 Line-Side Output Cable Driver (SDI_OUT1+, SDI_OUT2+)
          1. 7.3.5.1.1 Output Amplitude (VOD)
          2. 7.3.5.1.2 Output Pre-Emphasis
          3. 7.3.5.1.3 Output Slew Rate
          4. 7.3.5.1.4 Output Polarity Inversion
        2. 7.3.5.2 Host-Side 100-Ω Output Driver (OUT0±)
      6. 7.3.6 Status Indicators and Interrupts
        1. 7.3.6.1 SD_N (Signal Detect)
        2. 7.3.6.2 INT_N (Interrupt)
    4. 7.4 Device Functional Modes
      1. 7.4.1 System Management Bus (SMBus) Mode
        1. 7.4.1.1 SMBus Read and Write Transaction
          1. 7.4.1.1.1 SMBus Write Operation Format
          2. 7.4.1.1.2 SMBus Read Operation Format
      2. 7.4.2 Serial Peripheral Interface (SPI) Mode
        1. 7.4.2.1 SPI Read and Write Transactions
        2. 7.4.2.2 SPI Write Transaction Format
        3. 7.4.2.3 SPI Read Transaction Format
        4. 7.4.2.4 SPI Daisy Chain
    5. 7.5 Register Maps
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 SMPTE Requirements and Specifications
      2. 8.1.2 LMH1208 and LMH1228 Compatibility
    2. 8.2 Typical Applications
      1. 8.2.1 Dual Cable Driver
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Distribution Amplifier
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Board Stack-Up and Ground References
      2. 10.1.2 High-Speed PCB Trace Routing and Coupling
      3. 10.1.3 Anti-Pads
      4. 10.1.4 BNC Connector Layout and Routing
      5. 10.1.5 Power Supply and Ground Connections
      6. 10.1.6 Footprint Recommendations
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Export Control Notice
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Package Option Addendum
      1. 12.1.1 Packaging Information
      2. 12.1.2 Tape and Reel Information

Package Options

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

7.3.3 Input Signal Detect

IN0 has a signal detect circuit to monitor the presence or absence of an input signal. When the input signal amplitude for the selected input exceeds the signal detect assert threshold, the LMH1208 operates in normal operation mode.

In the absence of an input signal, the LMH1208 automatically goes into Power Save Mode to conserve power dissipation. When a valid signal is detected, the LMH1208 automatically exits Power Save Mode and returns to the normal operation mode. If the ENABLE pin is pulled low, the LMH1208 is forced into Power-Down Mode. In Power Save Mode, both the signal detect circuit and the serial interface remain active. In Power-Down Mode, only the serial interface remains active.

Users can monitor the status of the signal detect with the SD_N pin or through register programming.

Table 3. Input Signal Detect Modes of Operation

ENABLE SIGNAL INPUT OPERATING MODE
H 100-Ω signal input at IN0± Normal operation
Signal Detector at IN0±
Serial interface active
H No signal at IN0± Power Save Mode
Signal Detector at IN0±
Serial interface active
L Input signal ignored Power-Down Mode
Forced device power down
Serial interface active