JAJSFM3E February   2015  – June 2018 LMH1218

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      SPI概略回路図
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 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
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Recommended SMBus Interface AC Timing Specifications
    7. 7.7 Serial Parallel Interface (SPI) Bus Interface AC Timing Specifications
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Loss of Signal Detector
      2. 8.3.2 Continuous Time Linear Equalizer (CTLE)
      3. 8.3.3 2:1 Multiplexer
      4. 8.3.4 Clock and Data Recovery
      5. 8.3.5 Eye Opening Monitor (EOM)
      6. 8.3.6 Fast EOM
        1. 8.3.6.1 SMBus Fast EOM Operation
        2. 8.3.6.2 SPI Fast EOM Operation
      7. 8.3.7 LMH1218 Device Configuration
        1. 8.3.7.1 MODE_SEL
        2. 8.3.7.2 ENABLE
        3. 8.3.7.3 LOS_INT_N
        4. 8.3.7.4 LOCK
        5. 8.3.7.5 SMBus MODE
        6. 8.3.7.6 SMBus READ/WRITE Transaction
        7. 8.3.7.7 SPI Mode
          1. 8.3.7.7.1 SPI READ/WRITE Transaction
          2. 8.3.7.7.2 SPI Write Transaction Format
          3. 8.3.7.7.3 SPI Read Transaction Format
        8. 8.3.7.8 SPI Daisy Chain
          1. 8.3.7.8.1 SPI Daisy Chain Write Example
          2. 8.3.7.8.2 SPI Daisy Chain Write Read Example
            1. 8.3.7.8.2.1 SPI Daisy Chain Length of Daisy Chain Illustration
      8. 8.3.8 Power-On Reset
    4. 8.4 Device Functional Modes
    5. 8.5 Programming
    6. 8.6 Register Maps
      1. 8.6.1 Global Registers
      2. 8.6.2 Receiver Registers
      3. 8.6.3 CDR Registers
      4. 8.6.4 Transmitter Registers
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 General Guidance for All Applications
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
    3. 9.3 Do's and Don'ts
    4. 9.4 Initialization Set Up
      1. 9.4.1 Selective Data Rate Lock
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Solder Profile
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 デバイス・サポート
      1. 12.1.1 開発サポート
    2. 12.2 ドキュメントのサポート
      1. 12.2.1 関連資料
    3. 12.3 ドキュメントの更新通知を受け取る方法
    4. 12.4 コミュニティ・リソース
    5. 12.5 商標
    6. 12.6 静電気放電に関する注意事項
    7. 12.7 Glossary
  13. 13メカニカル、パッケージ、および注文情報

8.3.2 Continuous Time Linear Equalizer (CTLE)

The LMH1218 has receive-side equalization, and a key part is the Continuous Time Linear Equalizer (CTLE). This circuit operates on the received differential signal and compensates for frequency-dependent loss due to the transmission media. The CTLE applies gain to the input signal. This gain varies over frequency: higher frequencies are boosted more than lower frequencies. The CTLE works to restore the input signal to full amplitude across a wide range of frequencies.

The CTLE consists of 4 stages with each stage having two boost control bits. This allows 256 different boost settings. CTLE boost levels are determined by summing the boost levels of the 4 stages. The CTLE is configured manually. Refer to LMH1218 Programming Guide (SNLU174) on how to quickly select the most appropriate CTLE boost setting.

There are two CTLEs, one for each input, IN0 and IN1. Only one CTLE is enabled at a time, according to the user input channel selection. If IN0 is selected, the CTLE for IN0 is powered on and the IN1 CTLE is powered off. The CTLE compensates for up to 27 dB of loss at 6 GHz. The CTLE is able to handle low loss channels without over-equalizing by bypassing the CTLE.