SNAS724A February   2018  – April 2018 LMK05028

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Block Diagram
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
    2. 6.1 Device Start-Up Modes
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Diagrams
    7. 7.7 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Output Clock Test Configurations
  9. 9 Detailed Description
    1. 9.1 Overview
      1. 9.1.1 ITU-T G.8262 (SyncE) Standards Compliance
    2. 9.2 Functional Block Diagrams
      1. 9.2.1 PLL Architecture Overview
      2. 9.2.2 3-Loop Mode
        1. 9.2.2.1 PLL Output Clock Phase Noise Analysis in 3-Loop Mode
      3. 9.2.3 2-Loop REF-DPLL Mode
      4. 9.2.4 2-Loop TCXO-DPLL Mode
      5. 9.2.5 PLL Configurations for Common Applications
    3. 9.3 Feature Description
      1. 9.3.1  Oscillator Input (XO_P/N)
      2. 9.3.2  TCXO/OCXO Input (TCXO_IN)
      3. 9.3.3  Reference Inputs (INx_P/N)
      4. 9.3.4  Clock Input Interfacing and Termination
      5. 9.3.5  Reference Input Mux Selection
        1. 9.3.5.1 Automatic Input Selection
        2. 9.3.5.2 Manual Input Selection
      6. 9.3.6  Hitless Switching
      7. 9.3.7  Gapped Clock Support on Reference Inputs
      8. 9.3.8  Input Clock and PLL Monitoring, Status, and Interrupts
        1. 9.3.8.1 XO Input Monitoring
        2. 9.3.8.2 TCXO Input Monitoring
        3. 9.3.8.3 Reference Input Monitoring
          1. 9.3.8.3.1 Reference Validation Timer
          2. 9.3.8.3.2 Amplitude Monitor
          3. 9.3.8.3.3 Missing Pulse Monitor (Late Detect)
          4. 9.3.8.3.4 Runt Pulse Monitor (Early Detect)
          5. 9.3.8.3.5 Frequency Monitoring
          6. 9.3.8.3.6 Phase Valid Monitor for 1-PPS Inputs
        4. 9.3.8.4 PLL Lock Detectors
        5. 9.3.8.5 Tuning Word History
        6. 9.3.8.6 Status Outputs
        7. 9.3.8.7 Interrupt
      9. 9.3.9  PLL Channels
        1. 9.3.9.1  PLL Frequency Relationships
        2. 9.3.9.2  Analog PLL (APLL)
        3. 9.3.9.3  APLL XO Doubler
        4. 9.3.9.4  APLL Phase Frequency Detector (PFD) and Charge Pump
        5. 9.3.9.5  APLL Loop Filter
        6. 9.3.9.6  APLL Voltage Controlled Oscillator (VCO)
          1. 9.3.9.6.1 VCO Calibration
        7. 9.3.9.7  APLL VCO Post-Dividers (P1, P2)
        8. 9.3.9.8  APLL Fractional N Divider (N) With SDM
        9. 9.3.9.9  REF-DPLL Reference Divider (R)
        10. 9.3.9.10 TCXO/OCXO Input Doubler and M Divider
        11. 9.3.9.11 TCXO Mux
        12. 9.3.9.12 REF-DPLL and TCXO-DPLL Time-to-Digital Converter (TDC)
        13. 9.3.9.13 REF-DPLL and TCXO-DPLL Loop Filter
        14. 9.3.9.14 REF-DPLL and TCXO-DPLL Feedback Dividers
      10. 9.3.10 Output Clock Distribution
      11. 9.3.11 Output Channel Muxes
        1. 9.3.11.1 TCXO/Ref Bypass Mux
      12. 9.3.12 Output Dividers
      13. 9.3.13 Clock Outputs (OUTx_P/N)
        1. 9.3.13.1 AC-Differential Output (AC-DIFF)
        2. 9.3.13.2 HCSL Output
        3. 9.3.13.3 LVCMOS Output (1.8 V, 2.5 V)
        4. 9.3.13.4 Output Auto-Mute During LOL or LOS
      14. 9.3.14 Glitchless Output Clock Start-Up
      15. 9.3.15 Clock Output Interfacing and Termination
      16. 9.3.16 Output Synchronization (SYNC)
      17. 9.3.17 Zero-Delay Mode (ZDM) Configuration
      18. 9.3.18 PLL Cascading With Internal VCO Loopback
    4. 9.4 Device Functional Modes
      1. 9.4.1 Device Start-Up Modes
        1. 9.4.1.1 EEPROM Mode
        2. 9.4.1.2 ROM Mode
      2. 9.4.2 PLL Operating Modes
        1. 9.4.2.1 Free-Run Mode
        2. 9.4.2.2 Lock Acquisition
        3. 9.4.2.3 Locked Mode
        4. 9.4.2.4 Holdover Mode
      3. 9.4.3 PLL Start-Up Sequence
      4. 9.4.4 Digitally-Controlled Oscillator (DCO) Mode
        1. 9.4.4.1 DCO Frequency Step Size
        2. 9.4.4.2 DCO Direct-Write Mode
      5. 9.4.5 Zero-Delay Mode (ZDM)
      6. 9.4.6 Cascaded PLL Operation
    5. 9.5 Programming
      1. 9.5.1 Interface and Control
      2. 9.5.2 I2C Serial Interface
        1. 9.5.2.1 I2C Block Register Transfers
      3. 9.5.3 SPI Serial Interface
        1. 9.5.3.1 SPI Block Register Transfer
      4. 9.5.4 Register Map Generation
      5. 9.5.5 General Register Programming Sequence
      6. 9.5.6 EEPROM Programming Flow
        1. 9.5.6.1 EEPROM Programming Using Register Commit (Method #1)
          1. 9.5.6.1.1 Write SRAM Using Register Commit
          2. 9.5.6.1.2 Program EEPROM
        2. 9.5.6.2 EEPROM Programming Using Direct SRAM Writes (Method #2)
          1. 9.5.6.2.1 Write SRAM Using Direct Writes
      7. 9.5.7 Read SRAM
      8. 9.5.8 Read EEPROM
      9. 9.5.9 EEPROM Start-Up Mode Default Configuration
    6. 9.6 Register Maps
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Device Start-Up Sequence
      2. 10.1.2 Power Down (PDN) Pin
      3. 10.1.3 Power Rail Sequencing, Power Supply Ramp Rate, and Mixing Supply Domains
        1. 10.1.3.1 Mixing Supplies
        2. 10.1.3.2 Power-On Reset (POR) Circuit
        3. 10.1.3.3 Powering Up From a Single-Supply Rail
        4. 10.1.3.4 Power Up From Split-Supply Rails
        5. 10.1.3.5 Non-Monotonic or Slow Power-Up Supply Ramp
      4. 10.1.4 Slow or Delayed XO Start-Up
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
    3. 10.3 Do's and Don'ts
  11. 11Power Supply Recommendations
    1. 11.1 Power Supply Bypassing
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Reliability
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Clock Architect
      2. 13.1.2 TICS Pro
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Community Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

9.3.8.4 PLL Lock Detectors

The loss-of-lock (LOL) status is available for each APLL and DPLL. The APLLs are monitored for loss-of-frequency lock only. The REF-DPLLs are monitored for both loss-of-frequency lock (LOFL) and loss-of-phase lock (LOPL). The DPLL lock threshold and loss-of-lock threshold are programmable for both LOPF and LOFL detectors.

Each DPLL frequency lock detector will clear its LOFL flag when the DPLL's frequency error relative the selected reference input is less than the lock ppm threshold. Otherwise, it will set the LOFL flag when the DPLL's frequency error is greater than the unlock ppm threshold. The ppm delta between the lock and unlock thresholds provides hysteresis to prevent the LOFL flag from toggling when the DPLL frequency error is crossing these thresholds.

A measurement averaging factor is also used in computing the frequency lock detector register settings. A higher averaging factor increases the measurement delay to set or clear the LOFL flag. Higher averaging may be useful when locking to an input with high wander or when the DPLL is configured with a narrow loop bandwidth. Note that higher averaging reduces the maximum frequency ppm thresholds that can be configured.

Each DPLL phase lock detector will clear its LOPL flag when the DPLL's phase error is less than the phase lock threshold. Otherwise, it will set the LOPL flag when greater than the phase unlock threshold.

The APLL and DPLL lock detector flags can be observed through the status pins and the status bits.

LMK05028 lmk05028-pll-monitor-fbd.gifFigure 39. DPLL and APLL Lock Detectors