SNAS852 june   2023 CDCE6214Q1TM

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Description (cont.)
  7. 6 Device Comparison
  8. 7 Pin Configuration and Functions
  9. 8 Specifications
    1. 8.1  Absolute Maximum Ratings
    2. 8.2  ESD Ratings
    3. 8.3  Recommended Operating Conditions
    4. 8.4  Thermal Information
    5. 8.5  EEPROM Characteristics
    6. 8.6  Reference Input, Single-Ended Characteristics
    7. 8.7  Reference Input, Differential Characteristics
    8. 8.8  Reference Input, Crystal Mode Characteristics
    9. 8.9  General-Purpose Input Characteristics
    10. 8.10 Triple Level Input Characteristics
    11. 8.11 Logic Output Characteristics
    12. 8.12 Phase Locked Loop Characteristics
    13. 8.13 Closed-Loop Output Jitter Characteristics
    14. 8.14 Input and Output Isolation
    15. 8.15 Buffer Mode Characteristics
    16. 8.16 PCIe Spread Spectrum Generator
    17. 8.17 LVCMOS Output Characteristics
    18. 8.18 LP-HCSL Output Characteristics
    19. 8.19 LVDS Output Characteristics
    20. 8.20 Output Synchronization Characteristics
    21. 8.21 Power-On Reset Characteristics
    22. 8.22 I2C-Compatible Serial Interface Characteristics
    23. 8.23 Timing Requirements, I2C-Compatible Serial Interface
    24. 8.24 Power Supply Characteristics
    25. 8.25 Typical Characteristics
  10. 9 Parameter Measurement Information
    1. 9.1 Reference Inputs
    2. 9.2 Outputs
    3. 9.3 Serial Interface
    4. 9.4 PSNR Test
    5. 9.5 Clock Interfacing and Termination
      1. 9.5.1 Reference Input
      2. 9.5.2 Outputs
  11. 10Detailed Description
    1. 10.1 Overview
    2. 10.2 Functional Block Diagram
    3. 10.3 Feature Description
      1. 10.3.1 Reference Block
        1. 10.3.1.1 Zero Delay Mode, Internal and External Path
      2. 10.3.2 Phase-Locked Loop (PLL)
        1. 10.3.2.1 PLL Configuration and Divider Settings
        2. 10.3.2.2 Spread Spectrum Clocking
        3. 10.3.2.3 Digitally-Controlled Oscillator and Frequency Increment or Decrement - Serial Interface Mode and GPIO Mode
      3. 10.3.3 Clock Distribution
        1. 10.3.3.1 Glitchless Operation
        2. 10.3.3.2 Divider Synchronization
        3. 10.3.3.3 Global and Individual Output Enable
      4. 10.3.4 Power Supplies and Power Management
      5. 10.3.5 Control Pins
    4. 10.4 Device Functional Modes
      1. 10.4.1 Operation Modes
        1. 10.4.1.1 Fall-Back Mode
        2. 10.4.1.2 Pin Mode
        3. 10.4.1.3 Serial Interface Mode
    5. 10.5 Programming
      1. 10.5.1 I2C Serial Interface
      2. 10.5.2 EEPROM
        1. 10.5.2.1 EEPROM - Cyclic Redundancy Check
        2. 10.5.2.2 Recommended Programming Procedure
        3. 10.5.2.3 EEPROM Access
          1. 10.5.2.3.1 Register Commit Flow
          2. 10.5.2.3.2 Direct Access Flow
        4. 10.5.2.4 Register Bits to EEPROM Mapping
  12. 11Application and Implementation
    1. 11.1 Application Information
    2. 11.2 Typical Application
      1. 11.2.1 Design Requirements
      2. 11.2.2 Detailed Design Procedure
      3. 11.2.3 Application Curves
    3. 11.3 Power Supply Recommendations
      1. 11.3.1 Power-Up Sequence
      2. 11.3.2 Decoupling
    4. 11.4 Layout
      1. 11.4.1 Layout Guidelines
      2. 11.4.2 Layout Examples
  13. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
      2. 12.1.2 Device Nomenclature
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

10.3.2.3 Digitally-Controlled Oscillator and Frequency Increment or Decrement - Serial Interface Mode and GPIO Mode

In this mode, the output clock frequency can be incremented or decremented by a fixed frequency step. The frequency step size is determined by the register R43[15:0]. This value is added or subtracted to the numerator of the sigma-delta modulator. Every rising edge of FREQ_INC signal increases the output frequency, while every rising edge of FREQ_DEC signal decreases the output frequency. There are two ways to trigger the increment or decrement:

  1. Appropriate configuration of the GPIOs and sending a FREQ_INC or FREQ_DEC signal through an external microcontroller or ASIC.
  2. Using register bit fields controlled through serial interface.

Table 10-7 Register Settings for Frequency Increment or Decrement Functionality
REGISTER BIT ADDRESSREGISTER BIT FIELD NAMEDESCRIPTION
R3[3]FREQ_INC_DEC_ENEnables/Disables DCO mode
R3[4]FREQ_INC_DEC_REG_MODESelects DCO trigger through GPIOs or Serial Interface.
R3[6:5]FREQ_DEC_REG, FREQ_INC_REGGenerates FREQ_INC or FREQ_DEC signal through serial Interface
R43[15:0]FREQ_INC_DEC_DELTAFrequency Increment or Decrement step size
Table 10-8 Computing Divider Settings in DCO Mode
PARAMETERSVALUE (EXAMPLE)DESCRIPTION
Input PFD Frequency (FPFD)25 MHzSet according to FPFD.
Expected VCO Frequency (FVCO)2457.6 MHzFVCO is set within the operating VCO range of 2335 MHz to 2625 MHz. FVCO is selected such that PSA/PSB/Output Divider is Integer.
Expected Output Frequency (FOUT)24.576 MHzPSA = 4, IOD = 25. FVCO = PSA × IOD × FOUT.
Expected step size (in ppm) (Fstep)0.1Every rising edge of FREQ_INC or FREQ_DEC would change the output by this step size.
N-divider Value (N)98INT(FVCO/FPFD)
Minimum Numerator value to meet 0ppb accuracy (Num)76These values are computed to meet accuracy requirement at output. Should be less than 224.
Minimum Denominator to meet 0ppb accuracy (Den)250
Minimum Denominator value to meet ppm step size (FDEN,min)101725.261/(Fstep × 1e6) / (FVCO/FPFD)
Final Denominator value (FDEN,final)500000FDEN,final should be greater than FDEN,min and less than 224. FDEN,final and FNUM,final should be integer multiple of Den and Num respectively. FDEN,final/Den = FNUM,final/Num
Final Numerator value (FNUM,final)152000
Increment or Decrement step size5This value should be less than 216-1. FDEN,final should be closest integer multiple of FDEN,min.