SPRACP4A December   2019  – June 2024 AM67 , AM67A , AM68 , AM68A , AM69 , AM69A , DRA821U , DRA821U-Q1 , DRA829J , DRA829J-Q1 , DRA829V , DRA829V-Q1 , TDA4AEN-Q1 , TDA4AH-Q1 , TDA4AL-Q1 , TDA4AP-Q1 , TDA4VE-Q1 , TDA4VEN-Q1 , TDA4VH-Q1 , TDA4VL-Q1 , TDA4VM , TDA4VM-Q1 , TDA4VP-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Overview
    2. 1.2 Supporting Documentation
  5. 2High-Speed Interface Design Guidance
    1. 2.1  Trace Impedance
    2. 2.2  Trace Lengths
    3. 2.3  Differential Signal Length Matching
    4. 2.4  Signal Reference Planes
    5. 2.5  Differential Signal Spacing
    6. 2.6  Additional Differential Signal Rules
    7. 2.7  Symmetry in the Differential Pairs
    8. 2.8  Connectors and Receptacles
    9. 2.9  Via Discontinuity Mitigation
    10. 2.10 Back-Drill Via Stubs
    11. 2.11 Via Anti-Pad Diameter
    12. 2.12 Equalize Via Count
    13. 2.13 Surface-Mount Device Pad Discontinuity Mitigation
    14. 2.14 Signal Bending
    15. 2.15 ESD and EMI Considerations
    16. 2.16 ESD and EMI Layout Rules
  6. 3Interface-Specific Design Guidance
    1. 3.1 USB Board Design and Layout Guidelines
      1. 3.1.1 USB Interface Schematic
        1. 3.1.1.1 Support Components
      2. 3.1.2 Routing Specifications
    2. 3.2 DisplayPort Board Design and Layout Guidelines
      1. 3.2.1 DP Interface Schematic
        1. 3.2.1.1 Support Components
      2. 3.2.2 Routing Specifications
    3. 3.3 PCIe Board Design and Layout Guidelines
      1. 3.3.1 PCIe Interface Schematic
        1. 3.3.1.1 Polarity Inversion
        2. 3.3.1.2 Lane Swap
        3. 3.3.1.3 REFCLK Connections
        4. 3.3.1.4 Coupling Capacitors
      2. 3.3.2 Routing Specifications
    4. 3.4 MIPI® D-PHY (CSI2, DSI) Board Design and Layout Guidelines
      1. 3.4.1 CSI-2®, DSI® Interface Schematic
      2. 3.4.2 Routing Specifications
      3. 3.4.3 Frequency-Domain Specification Guidelines
    5. 3.5 UFS Board Design and Layout Guidelines
      1. 3.5.1 UFS Interface Schematic
      2. 3.5.2 Routing Specifications
    6. 3.6 Q/SGMII Board Design and Layout Guidelines
      1. 3.6.1 Q/SGMII Interface Schematic
        1. 3.6.1.1 Coupling Capacitors
      2. 3.6.2 Routing Specifications
  7. 4Board Design Simulations
    1. 4.1 Board Model Extraction
    2. 4.2 Board-Model Validation
    3. 4.3 S-Parameter Inspection
    4. 4.4 Time Domain Reflectometry (TDR) Analysis
    5. 4.5 Simulation Integrity Analysis
      1. 4.5.1 Simulator Settings and Model Usage
      2. 4.5.2 Simulation Parameters
      3. 4.5.3 Simulation Methodology
    6. 4.6 Reviewing Simulation Results
  8. 5References
  9. 6Revision History

2.16 ESD and EMI Layout Rules

  • Place ESD and EMI protection devices as close as possible to the connector.
  • Keep any unprotected traces away from protected traces to minimize EMI coupling.
  • Incorporate 60% voids under the ESD and EMI component signal pads to reduce losses.
  • Use 0402 0Ω resistors for common-mode filter (CMF) no-stuff options because larger components typically introduce more loss that the CMF.
  • Place any required signal pair AC coupling capacitors on the protected side of the CMF and as close as possible to the CMF.
  • If vias are needed to transition to the CMF layer, make sure that the vias are as close as possible to the CMF.
  • Keep the overall routing of AC coupling capacitors + CMF + ESD protection as short and as close as possible to the connector.