SPRACN9F May   2023  – August 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.   Jacinto7 AM6x/TDA4x/DRA8x LPDDR4 Design Guidelines
  3.   Trademarks
  4. 1Overview
    1. 1.1 Supporting Documentation
    2. 1.2 Board Designs Supported
    3. 1.3 General Board Layout Guidelines
    4. 1.4 PCB Stack-Up
    5. 1.5 Bypass Capacitors
      1. 1.5.1 Bulk Bypass Capacitors
      2. 1.5.2 High-Speed Bypass Capacitors
    6. 1.6 Velocity Compensation
  5. 2LPDDR4 Board Design and Layout Guidance
    1. 2.1  LPDDR4 Introduction
    2. 2.2  LPDDR4 Device Implementations Supported
    3. 2.3  LPDDR4 Interface Schematics
    4. 2.4  Compatible JEDEC LPDDR4 Devices
    5. 2.5  Placement
    6. 2.6  LPDDR4 Keepout Region
    7. 2.7  Net Classes
    8. 2.8  LPDDR4 Signal Termination
    9. 2.9  LPDDR4 VREF Routing
    10. 2.10 LPDDR4 VTT
    11. 2.11 CK, CMD_ADDR, and CTRL Topologies
    12. 2.12 Data Group Topologies
    13. 2.13 CK, CMD_ADDR, and CTRL Routing Specification
    14. 2.14 Data Group Routing Specification
    15. 2.15 Channel, Byte, and Bit Swapping
  6. 3LPDDR4 Board Design Simulations
    1. 3.1 Board Model Extraction
    2. 3.2 Board-Model Validation
    3. 3.3 S-Parameter Inspection
    4. 3.4 Time Domain Reflectometry (TDR) Analysis
    5. 3.5 Simulation Integrity Analysis
      1. 3.5.1 Simulation Setup
      2. 3.5.2 Simulation Parameters
      3. 3.5.3 Simulation Targets
        1. 3.5.3.1 Waveform Quality
        2. 3.5.3.2 Eye Quality
        3. 3.5.3.3 Delay Report
        4. 3.5.3.4 Mask Report
    6. 3.6 Design Example
      1. 3.6.1 Stack-Up
      2. 3.6.2 Routing
      3. 3.6.3 Model Verification
      4. 3.6.4 Simulation Results
  7. 4Revision History

1.5 Bypass Capacitors

It is recommended to follow TI's EVM for the decoupling capacitor count and selection. The sections that follow provide some general guidance for decoupling, but recommendation is to follow the EVM. This is because the DDR has been tested/validated on the EVM. Power decoupling also include PCB design elements, so decoupling changes may be required to account for PCB differences.