ZHCSDR9D July   2012  – May 2015 DS125BR401

PRODUCTION DATA.  

  1. 特性
  2. 应用范围
  3. 说明
  4. 典型应用
  5. 修订历史记录
  6. 说明(续)
  7. Pin Configuration and Functions
  8. Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Electrical Characteristics — Serial Management Bus Interface
    7. 8.7 Typical Characteristics
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Typical 4-Level Input Thresholds
    4. 9.4 Device Functional Modes
      1. 9.4.1 Pin Control Mode
      2. 9.4.2 SMBUS Mode
    5. 9.5 Programming
      1. 9.5.1 PCIe Signal Integrity
        1. 9.5.1.1 RX-Detect in SAS/SATA (up to 6 Gbps) Applications
          1. 9.5.1.1.1 Signal Detect Control for Datarates Above 8 Gbps
        2. 9.5.1.2 MODE Operation With SMBus Registers
      2. 9.5.2 SMBUS Master Mode
      3. 9.5.3 System Management Bus (SMBus) and Configuration Registers
        1. 9.5.3.1 Transfer of Data Through the SMBus
        2. 9.5.3.2 SMBus Transactions
        3. 9.5.3.3 Writing a Register
        4. 9.5.3.4 Reading a Register
    6. 9.6 Register Maps
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 3.3-V or 2.5-V Supply Mode Operation
    2. 11.2 Power Supply Bypassing
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 PCB Layout Considerations for Differential Pairs
    2. 12.2 Layout Example
  13. 13器件和文档支持
    1. 13.1 文档支持
      1. 13.1.1 相关文档
    2. 13.2 Community Resources
    3. 13.3 商标
    4. 13.4 静电放电警告
    5. 13.5 术语表
  14. 14机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

12 Layout

12.1 Layout Guidelines

12.1.1 PCB Layout Considerations for Differential Pairs

The CML inputs and LPDS outputs have been optimized to work with interconnects using a controlled differential impedance of 85 Ω to 100 Ω. It is preferable to route differential lines exclusively on one layer of the board, particularly for the input traces. The use of vias should be avoided if possible. If vias must be used, they should be used sparingly and must be placed symmetrically for each side of a given differential pair. Whenever differential vias are used the layout must also provide for a low inductance path for the return currents as well. Route the differential signals away from other signals and noise sources on the printed circuit board. See AN-1187 Leadless Leadframe Package (LLP) Application Report (SNOA401) for additional information on QFN (WQFN) packages.

Figure 26 depicts different transmission line topologies which can be used in various combinations to achieve the optimal system performance. Impedance discontinuities at the differential via can be minimized or eliminated by increasing the swell around each hole and providing for a low inductance return current path. When the via structure is associated with thick backplane PCB, further optimization such as back drilling is often used to reduce the detrimental high frequency effects of stubs on the signal path.

12.2 Layout Example

DS125BR401 30198710.gifFigure 26. Typical Routing Options