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

10.3.1 Reference Block

A reference clock to the PLL is fed to pins 1 (SECREF_P) and 2 (SECREF_N) or to pins 5 (PRIREF_P) and 6 (PRIREF_N). There are multiple input stages to accommodate various clock references. Pins 1 and 2 can be used to connect a XTAL across the clock, or provide an external single-ended LVCMOS clock or differential clock. These modes are selectable through register programming. When differential mode is selected, appropriated biasing is applied to the pin. In case of differential mode, an external AC-coupling capacitor is required. When XTAL or LVCMOS mode is selected, biasing circuitry is disengaged. Pins 5 and 6 can be used to provide an external single-ended LVCMOS clock or a differential clock.

The reference MUX selects the reference clock for the PLL. Setting REFSEL pin = L selects SECREF input, while setting REFSEL pin = H selects PRIREF Input. Alternatively, this can be configured through the register settings.

Table 10-1 Reference Input Selection
REGISTER BIT ADDRESSREGISTER BIT FIELD NAMEVALUEDESCRIPTION
R2[1:0]REFSEL_SW0h or 1hInput Reference Mux controlled through Pin 4 (REFSEL)
(Default: 0h)2hPin1/Pin 2 SECREF Input selected. This is independent of Pin 4 status.
3hPin 5/Pin 6 PRIREF Input selected. This is independent of Pin 4 status.
R24[1:0]IP_SECREF_BUF_SEL0hXO enabled. Valid for SECREF pins.
(Default: 0h)1hLVCMOS Buffer enabled. Valid for SECREF pins.
2h or 3hDifferential Buffer enabled. Valid for SECREF pins.
R24[15]IP_PRIREF_BUF_SEL0hLVCMOS Buffer enabled. Valid for PRIREF pins.
(Default: 0h)1hDifferential Buffer enabled. Valid for PRIREF pins.

A reference divider or a clock-doubler can be engaged to further multiply (2x) or divide the reference clock to the PLL. IP_RDIV[7:0] can be used to set the value of the divider. Setting this to 00h would enable the doubler.

The output clock from the reference block can be bypassed to the OUT0 and other output channels. The bypassed clock is selectable between the Input clock or PFD clock. See Table 10-9.

The SECREF_P and SECREF_N pins provide a crystal oscillator stage to drive a fundamental mode crystal in the range of 10 MHz to 50 MHz. The crystal input stage integrates a tunable load capacitor array up to 9 pF and programmable through R24[12:8]. The drive capability of the oscillator is programmable through R24[5:2].

The LVCMOS input buffer threshold voltage follows VDD_REF. This device can be used as a level shifter because the outputs have separate supplies.