TIDUEY8 March   2023

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Design Block Diagram
    2. 2.2 Highlighted Products
      1. 2.2.1 LMK04832-SP
      2. 2.2.2 LMX2615-SP
      3. 2.2.3 CDCLVP111-SP
      4. 2.2.4 ADC12DJ3200QML-SP
    3. 2.3 Design Steps
      1. 2.3.1 Multiple JESD204B Synchronization Requirements
      2. 2.3.2 Clock Tree Design
        1. 2.3.2.1 Clock Frequency Plan
        2. 2.3.2.2 Clock Tree Components
          1. 2.3.2.2.1 Clock Reference
          2. 2.3.2.2.2 Clock Reference Buffer
          3. 2.3.2.2.3 Clock Distribution
          4. 2.3.2.2.4 Frequency Synthesis
        3. 2.3.2.3 Phase Delay Adjustment Options
        4. 2.3.2.4 Phase-Noise Optimization
        5. 2.3.2.5 Single-Event Effects (SEE) Considerations
        6. 2.3.2.6 Expanding Clock Tree for MIMO Systems
      3. 2.3.3 Power Management
        1. 2.3.3.1 Power Design Considerations
        2. 2.3.3.2 Radiation Hardened (Rad-Hard) Power Tree
          1. 2.3.3.2.1 Radiation-Hardness-Assured (RHA) Load-Switches
          2. 2.3.3.2.2 Radiation-Hardness-Assured (RHA) DC/DC Buck Converter
          3. 2.3.3.2.3 Radiation-Hardness-Assured (RHA) Low-Dropout (LDO) Regulators
            1. 2.3.3.2.3.1 3.3-V Linear Regulator
            2. 2.3.3.2.3.2 4.5-V Linear Regulator
        3. 2.3.3.3 Overcurrent Detection Circuit
  8. 3Getting Started Hardware and Software
    1. 3.1 Hardware Configuration
      1. 3.1.1 Clocking Board Setup
        1. 3.1.1.1 Power Supply
        2. 3.1.1.2 Input Reference Signals
        3. 3.1.1.3 Input sync Signal
        4. 3.1.1.4 Output Signals
        5. 3.1.1.5 Programming Interface
        6. 3.1.1.6 FMC+ Adapter Board Setup
        7. 3.1.1.7 ADC12DJ3200 EVM Setup
        8. 3.1.1.8 TSW14J57EVM Setup
        9. 3.1.1.9 Multichannel Synchronization Setup
    2. 3.2 Software
      1. 3.2.1 Software Required
      2. 3.2.2 Clocking Board Programming Sequence
      3. 3.2.3 ADC12DJ3200CVAL EVM Programming Sequence
      4. 3.2.4 TSW14J57EVM Evaluation Programming Sequence
  9. 4Testing and Results
    1. 4.1 Test Setup
    2. 4.2 Results
      1. 4.2.1 Phase Noise Measurement Results
      2. 4.2.2 Multichannel Clock Phase Alignment
      3. 4.2.3 Signal Chain Performance
      4. 4.2.4 Channel-to-Channel Skew Measurement
    3. 4.3 Summary and Conclusion
  10. 5Design and Documentation Support
    1. 5.1 Design Support
      1. 5.1.1 Schematics
      2. 5.1.2 Bill of Materials
    2. 5.2 Documentation Support
    3. 5.3 Support Resources
    4. 5.4 Trademarks
  11. 6About the Authors
    1. 6.1 Acknowledgments

2.3.3.1 Power Design Considerations

Low-noise power supply is critical to the performance of the analog front end. Figure 2-11 shows the noise coupling paths from the power supply to the analog front end. Figure 2-11 also shows the impact of the power-supply noise on the output spectrum of the data converter. As previously mentioned, the data converter spectrum has two components due to power supply noise:

  • Direct-coupled frequency component
  • Modulated frequency component

Consider the following for a robust design:

  • Reduce the noise at the source
  • Eliminate or minimize the coupling path
  • Desensitize the load to noise

In the analog front end, the clock power rails and the analog power rails of data converters need low-noise power supply. Take necessary precautions in terms of using a post regulator for the DC/DC converter or appropriate filtering of the DC/DC converter output.

The DC/DC converter followed by an LDO has tradeoffs in terms of size and thermal performance. If there are multiple switch-mode power supplies synchronizing, these can reduce beat frequencies and EMI.

GUID-20221202-SS0I-TPKM-PXJB-P0NPS29XLLKW-low.svgFigure 2-11 Noise Coupling