SPRABJ8D September   2022  – May 2025 AM2612 , AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1 , AM263P2 , AM263P2-Q1 , AM263P4 , AM263P4-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 Power
    1. 2.1 Discrete DC-DC Power Solution
    2. 2.2 Integrated PMIC Power Solution
    3. 2.3 Power Decoupling and Filtering
      1. 2.3.1 ADC/DAC Voltage Reference Decoupling
    4. 2.4 Estimated Power Consumption
    5. 2.5 Power Distribution Network
      1. 2.5.1 Simulations
        1. 2.5.1.1 Core Digital Power 1.2V
        2. 2.5.1.2 Digital and Analog I/O Power 3.3V
    6. 2.6 eFuse Power
  6. 3 Clocking
    1. 3.1 Crystal and Oscillator Input Options
    2. 3.2 Output Clock Generation
    3. 3.3 Crystal Selection and Shunt Capacitance
    4. 3.4 Crystal Placement and Routing
  7. 4 Resets
  8. 5 Bootstrapping
    1. 5.1 SOP Signal Implementation
  9. 6 OSPI and QSPI Memory Implementation
    1. 6.1 ROM OSPI and QSPI Boot Requirements
      1. 6.1.1 AM263x QSPI Boot Pin Requirements
      2. 6.1.2 AM263Px OSPI and QSPI Boot Pin Requirements
      3. 6.1.3 AM261x OSPI and QSPI Boot Pin Requirements
    2. 6.2 Additional OSPI and QSPI References
  10. 7 Debug Interfaces
    1. 7.1 JTAG Emulators and Trace
    2. 7.2 UART
  11. 8 USB
    1. 8.1 USB Device Mode
    2. 8.2 USB Host Mode
  12. 9 Multiplexed Peripherals
  13. 10Digital Peripherals
    1. 10.1 General Digital Peripheral Routing Guidelines
    2. 10.2 Trace Length Matching
  14. 11Analog Peripherals
    1. 11.1 General Analog Peripheral Routing Guidelines
      1. 11.1.1 Resolver ADC Routing Guidelines
  15. 12Layer Stackup
    1. 12.1 Key Stackup Features
  16. 13Vias
  17. 14BGA Power Fan-Out and Decoupling Placement
    1. 14.1 Ground Return
      1. 14.1.1 Ground Return - ZCZ Package AM26x Devices
      2. 14.1.2 Ground Return - ZNC and ZFG Package AM261x Devices
    2. 14.2 1.2V Core Digital Power
      1. 14.2.1 1.2V Core Digital Power Key Layout Considerations - ZCZ
      2. 14.2.2 1.2V Core Digital Power Key Layout Considerations - ZFG
    3. 14.3 3.3V Digital and Analog Power
      1. 14.3.1 3.3V I/O Power Key Layout Considerations - ZCZ
      2. 14.3.2 3.3V I/O Power Key Layout Considerations - ZFG
    4. 14.4 1.8V Digital and Analog Power
      1. 14.4.1 1.8V Key Layout Considerations - ZCZ
      2. 14.4.2 1.8V Key Layout Considerations - ZFG
  18. 15Summary
  19. 16References
  20. 17Revision History

3.3 Crystal Selection and Shunt Capacitance

In crystal operating mode, the AM26x can be interfaced to a wide variety of compatible crystals. Based on PCB parasitic capacitance and crystal selected, the additional load capacitance needs to be modified to achieve the best start-up stability and frequency accuracy.

For full crystal loading tolerances, see the device-specific AM26x data sheet.