SPRAD85A March   2023  – September 2024 AM62A3 , AM62A3-Q1 , AM62A7 , AM62A7-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
    1. 1.1 Before Getting Started With the Custom Board Design
    2. 1.2 Processor Selection
    3. 1.3 Technical Documentation
      1. 1.3.1 Updated SK Schematics With Design, Review and Cad Notes Added
      2. 1.3.2 FAQs to Support Custom Board Design
    4. 1.4 Design Documentation
  5. 2 Block Diagram
    1. 2.1 Constructing the Block Diagram
    2. 2.2 Configuring the Boot Mode
    3. 2.3 Confirming PinMux (PinMux Configuration)
  6. 3 Power Supply
    1. 3.1 Power Supply Architecture
      1. 3.1.1 Integrated Power
      2. 3.1.2 Discrete Power
    2. 3.2 Power (Supply) Rails
      1. 3.2.1 Core Supply
      2. 3.2.2 Peripheral Power Supply
      3. 3.2.3 Dynamic Switching Dual-Voltage IO Supply LDO
      4. 3.2.4 Internal LDOs for IO Groups (Processor)
      5. 3.2.5 Dual-Voltage IOs (for Processor IO Groups)
      6. 3.2.6 VPP (eFuse ROM programming) Supply
    3. 3.3 Determining Board Power Requirements
    4. 3.4 Power Supply Filters
    5. 3.5 Power Supply Decoupling and Bulk Capacitors
      1. 3.5.1 Note on PDN Target Impedance
    6. 3.6 Power Supply Sequencing
    7. 3.7 Supply Diagnostics
    8. 3.8 Power Supply Monitoring
  7. 4 Processor Clocking
    1. 4.1 Processor External Clock Source
      1. 4.1.1 Unused WKUP_LFOSC0
      2. 4.1.2 LVCMOS Digital Clock Source
      3. 4.1.3 Crystal Selection
    2. 4.2 Processor Clock Outputs
  8. 5 JTAG (Joint Test Action Group)
    1. 5.1 JTAG / Emulation
      1. 5.1.1 Configuration of JTAG / Emulation
      2. 5.1.2 Implementation of JTAG / Emulation
      3. 5.1.3 Connection of JTAG Interface Signals
  9. 6 Configuration (Processor) and Initialization (Processor and Device)
    1. 6.1 Processor Reset
    2. 6.2 Latching of Boot Mode Configuration
    3. 6.3 Resetting the Attached Devices
    4. 6.4 Watchdog Timer
  10. 7 Processor Peripherals
    1. 7.1  Selecting Peripherals Across Domains
    2. 7.2  Memory (DDRSS)
      1. 7.2.1 Processor DDR Subsystem and Device Register Configuration
      2. 7.2.2 Calibration Resistor Connection for DDRSS
      3. 7.2.3 Attached Memory Device ZQ and Reset_N Connection
    3. 7.3  Media and Data Storage Interfaces
    4. 7.4  Common Platform Ethernet Switch 3-port Gigabit (CPSW3G - for Ethernet Interface)
    5. 7.5  Programmable Real-Time Unit Subsystem (PRUSS)
    6. 7.6  Universal Serial Bus (USB) Subsystem
    7. 7.7  General Connectivity Peripherals
    8. 7.8  Display Subsystem (DSS)
    9. 7.9  Camera Subsystem (CSI)
    10. 7.10 Connection of Processor Power Supply Pins, Unused Peripherals and IOs
      1. 7.10.1 External Interrupt (EXTINTn)
      2. 7.10.2 Reserved (RSVD) Pins
  11. 8 Interfacing of Processor IOs ( LVCMOS or Open-Drain or Fail-Safe Type IO Buffers) and Simulations
  12. 9 Processor Current Rating and Thermal Analysis
    1. 9.1 Power Estimation
    2. 9.2 Maximum Current Rating for Different Supply Rails
    3. 9.3 Power Modes
    4. 9.4 Thermal Design Guidelines
      1. 9.4.1 VTM (Voltage Thermal Management Module)
  13. 10Schematics:- Design, Capture, Entry and Review
    1. 10.1 Selection of Components and Values
    2. 10.2 Schematic Design and Capture
    3. 10.3 Schematics Review
  14. 11Floor Planning, Layout, Routing Guidelines, Board Layers and Simulation
    1. 11.1 Escape Routing for PCB Design
    2. 11.2 LPDDR4 Design and Layout Guidelines
    3. 11.3 High-Speed Differential Signals Routing Guidelines
    4. 11.4 Board Layer Count and Stack-up
      1. 11.4.1 Simulation Recommendations
    5. 11.5 Reference for Steps to be Followed for Running Simulation
  15. 12Custom Board Assembly and Testing
    1. 12.1 Guidelines and Board Bring-up Tips
  16. 13Device Handling and Assembly
    1. 13.1 Soldering Recommendations
      1. 13.1.1 Additional References
  17. 14References
    1. 14.1 Processor Specific
    2. 14.2 Common
  18. 15Terminology
  19. 16Revision History

11.4 Board Layer Count and Stack-up

An important constraint in determining layer count is the number of layers required to implement the high-speed LPDDR4 memory interface. Memory layout meeting the recommended guidelines typically requires the number of layers used in the Starter Kit (TI recommended). Optimization of layer count could be possible based on the custom board design and functionalities.

Refer the AM62Ax / AM62Px LPDDR4 Board Design and Layout Guidelines available on TI.com for further guidance and recommendations for implementing the LPDDR4 memory interface.

Refer the AM62Ax Escape Routing for PCB Design as a guideline during board layout. Use of TI Via Channel Array (VCA) technology with the AMB package supports layer optimization.