SNLS474E February   2015  – June 2018 LMH1218

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified SPI Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Descriptions – SPI Mode/ Mode_SEL = 1 kΩ to VDD
    2.     Pin Descriptions – SMBUS Mode/ MODE_SEL = 1 kΩ to GND
  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 AC Timing Specifications
    7. 6.7 Serial Parallel Interface (SPI) Bus Interface AC 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 Loss of Signal Detector
      2. 7.3.2 Continuous Time Linear Equalizer (CTLE)
      3. 7.3.3 2:1 Multiplexer
      4. 7.3.4 Clock and Data Recovery
      5. 7.3.5 Eye Opening Monitor (EOM)
      6. 7.3.6 Fast EOM
        1. 7.3.6.1 SMBus Fast EOM Operation
        2. 7.3.6.2 SPI Fast EOM Operation
      7. 7.3.7 LMH1218 Device Configuration
        1. 7.3.7.1 MODE_SEL
        2. 7.3.7.2 ENABLE
        3. 7.3.7.3 LOS_INT_N
        4. 7.3.7.4 LOCK
        5. 7.3.7.5 SMBus MODE
        6. 7.3.7.6 SMBus READ/WRITE Transaction
        7. 7.3.7.7 SPI Mode
          1. 7.3.7.7.1 SPI READ/WRITE Transaction
          2. 7.3.7.7.2 SPI Write Transaction Format
          3. 7.3.7.7.3 SPI Read Transaction Format
        8. 7.3.7.8 SPI Daisy Chain
          1. 7.3.7.8.1 SPI Daisy Chain Write Example
          2. 7.3.7.8.2 SPI Daisy Chain Write Read Example
            1. 7.3.7.8.2.1 SPI Daisy Chain Length of Daisy Chain Illustration
      8. 7.3.8 Power-On Reset
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
    6. 7.6 Register Maps
      1. 7.6.1 Global Registers
      2. 7.6.2 Receiver Registers
      3. 7.6.3 CDR Registers
      4. 7.6.4 Transmitter Registers
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 General Guidance for All Applications
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Do's and Don'ts
    4. 8.4 Initialization Set Up
      1. 8.4.1 Selective Data Rate Lock
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Solder Profile
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.7.8.1 SPI Daisy Chain Write Example

The following example make some assumptions:

The daisy-chain is 3 LMH1218 devices long, comprising Devices 1, 2, and 3 as shown in Figure 18. Therefore, each Basic SPI Transaction is 17x3 = 51 clocks long.

In Figure 19, the following occurs at the end of the transaction:

  • Write 0x5A to register 0x12 in Device 3
  • Write 0x3C to register 0x34 in Device 2
  • Write 0x00 to register 0x56 in Device 1

Note that the bits are shifted out of MOSI left to right. The MISO pin is not shown as it reflects shift register contents from a prior transaction.

LMH1218 MOSI_write_one_row_0x00_end.gifFigure 19. MOSI Write