SNAS786C July   2020  – July 2025 CDCE6214-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  EEPROM Characteristics
    6. 5.6  Reference Input, Single-Ended Characteristics
    7. 5.7  Reference Input, Differential Characteristics
    8. 5.8  Reference Input, Crystal Mode Characteristics
    9. 5.9  General-Purpose Input Characteristics
    10. 5.10 Triple Level Input Characteristics
    11. 5.11 Logic Output Characteristics
    12. 5.12 Phase Locked Loop Characteristics
    13. 5.13 Closed-Loop Output Jitter Characteristics
    14. 5.14 Input and Output Isolation
    15. 5.15 Buffer Mode Characteristics
    16. 5.16 PCIe Spread Spectrum Generator
    17. 5.17 LVCMOS Output Characteristics
    18. 5.18 LP-HCSL Output Characteristics
    19. 5.19 LVDS Output Characteristics
    20. 5.20 Output Synchronization Characteristics
    21. 5.21 Power-On Reset Characteristics
    22. 5.22 I2C-Compatible Serial Interface Characteristics
    23. 5.23 Timing Requirements, I2C-Compatible Serial Interface
    24. 5.24 Power Supply Characteristics
    25. 5.25 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1 Reference Inputs
    2. 6.2 Outputs
    3. 6.3 Serial Interface
    4. 6.4 PSNR Test
    5. 6.5 Clock Interfacing and Termination
      1. 6.5.1 Reference Input
      2. 6.5.2 Outputs
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Reference Block
        1. 7.3.1.1 Zero Delay Mode, Internal and External Path
      2. 7.3.2 Phase-Locked Loop (PLL)
        1. 7.3.2.1 PLL Configuration and Divider Settings
        2. 7.3.2.2 Spread Spectrum Clocking
        3. 7.3.2.3 Digitally-Controlled Oscillator and Frequency Increment or Decrement - Serial Interface Mode and GPIO Mode
      3. 7.3.3 Clock Distribution
        1. 7.3.3.1 Glitchless Operation
        2. 7.3.3.2 Divider Synchronization
        3. 7.3.3.3 Global and Individual Output Enable
      4. 7.3.4 Power Supplies and Power Management
      5. 7.3.5 Control Pins
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation Modes
        1. 7.4.1.1 Fall-Back Mode
        2. 7.4.1.2 Pin Mode
        3. 7.4.1.3 Serial Interface Mode
    5. 7.5 Programming
      1. 7.5.1 I2C Serial Interface
      2. 7.5.2 EEPROM
        1. 7.5.2.1 EEPROM - Cyclic Redundancy Check
        2. 7.5.2.2 Recommended Programming Procedure
        3. 7.5.2.3 EEPROM Access
          1. 7.5.2.3.1 Register Commit Flow
          2. 7.5.2.3.2 Direct Access Flow
        4. 7.5.2.4 Register Bits to EEPROM Mapping
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Power-Up Sequence
      2. 8.3.2 Decoupling
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
      2. 9.1.2 Device Nomenclature
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Package Option Addendum
    2. 11.2 Tape and Reel Information

8.4.1 Layout Guidelines

For this example, follow these guidelines:

  • Isolate inputs and outputs using a GND shield. Figure 8-5 routes all inputs and outputs as differential pairs.
  • Isolate outputs to adjacent outputs when generating multiple frequencies.
  • Isolate the crystal area, connect the GND pads of the crystal package and flood the adjacent area. Figure 8-6 shows a foot print which supports multiple crystal sizes.
  • Try to avoid impedance jumps in the fan-in and fan-out areas when possible.
  • Use five VIAs to connect the thermal pad to a solid GND plane. Full-through VIAs are preferred.
  • Place decoupling capacitors with small capacitance values very close to the supply pins. Try to place the capacitors very close on the same layer or directly on the backside layer. Larger values can be placed more far away. Figure 8-6 shows three decoupling capacitors close to the device. Ferrite beads are recommended to isolate the different frequency domains and the VDD_VCO domain.
  • Preferably use multiple VIAs to connect wide supply traces to the respective power planes.