SNAS918 May   2025 LMK5C23208A

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Diagrams
    7. 6.7 Typical Characteristics
  8. 7 Parameter Measurement Information
    1. 7.1 Differential Voltage Measurement Terminology
    2. 7.2 Output Clock Test Configurations
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
      1. 8.2.1 PLL Architecture Overview
      2. 8.2.2 DPLL
        1. 8.2.2.1 Independent DPLL Operation
        2. 8.2.2.2 Cascaded DPLL Operation
        3. 8.2.2.3 APLL Cascaded With DPLL
      3. 8.2.3 APLL-Only Mode
    3. 8.3 Feature Description
      1. 8.3.1  Oscillator Input (XO)
      2. 8.3.2  Reference Inputs
      3. 8.3.3  Clock Input Interfacing and Termination
      4. 8.3.4  Reference Input Mux Selection
        1. 8.3.4.1 Automatic Input Selection
        2. 8.3.4.2 Manual Input Selection
      5. 8.3.5  Hitless Switching
        1. 8.3.5.1 Hitless Switching With Phase Cancellation
        2. 8.3.5.2 Hitless Switching With Phase Slew Control
        3. 8.3.5.3 Hitless Switching With 1PPS Inputs
      6. 8.3.6  Gapped Clock Support on Reference Inputs
      7. 8.3.7  Input Clock and PLL Monitoring, Status, and Interrupts
        1. 8.3.7.1 XO Input Monitoring
        2. 8.3.7.2 Reference Input Monitoring
          1. 8.3.7.2.1 Reference Validation Timer
          2. 8.3.7.2.2 Frequency Monitoring
          3. 8.3.7.2.3 Missing Pulse Monitor (Late Detect)
          4. 8.3.7.2.4 Runt Pulse Monitor (Early Detect)
          5. 8.3.7.2.5 Phase Valid Monitor for 1PPS Inputs
        3. 8.3.7.3 PLL Lock Detectors
        4. 8.3.7.4 Tuning Word History
        5. 8.3.7.5 Status Outputs
        6. 8.3.7.6 Interrupt
      8. 8.3.8  PLL Relationships
        1. 8.3.8.1  PLL Frequency Relationships
          1. 8.3.8.1.1 APLL Phase Frequency Detector (PFD) and Charge Pump
          2. 8.3.8.1.2 APLL VCO Frequency
          3. 8.3.8.1.3 DPLL TDC Frequency
          4. 8.3.8.1.4 DPLL VCO Frequency
          5. 8.3.8.1.5 Clock Output Frequency
        2. 8.3.8.2  Analog PLLs (APLL1, APLL2)
        3. 8.3.8.3  APLL Reference Paths
          1. 8.3.8.3.1 APLL XO Doubler
          2. 8.3.8.3.2 APLL XO Reference (R) Divider
        4. 8.3.8.4  APLL Feedback Divider Paths
          1. 8.3.8.4.1 APLL N Divider With Sigma-Delta Modulator (SDM)
        5. 8.3.8.5  APLL Loop Filters (LF1, LF2)
        6. 8.3.8.6  APLL Voltage-Controlled Oscillators (VCO1, VCO2)
          1. 8.3.8.6.1 VCO Calibration
        7. 8.3.8.7  APLL VCO Clock Distribution Paths
        8. 8.3.8.8  DPLL Reference (R) Divider Paths
        9. 8.3.8.9  DPLL Time-to-Digital Converter (TDC)
        10. 8.3.8.10 DPLL Loop Filter (DLF)
        11. 8.3.8.11 DPLL Feedback (FB) Divider Path
      9. 8.3.9  Output Clock Distribution
      10. 8.3.10 Output Source Muxes
      11. 8.3.11 Output Channel Muxes
      12. 8.3.12 Output Dividers (OD)
      13. 8.3.13 SYSREF/1PPS Output
      14. 8.3.14 Output Delay
      15. 8.3.15 Clock Output Drivers
        1. 8.3.15.1 Differential Output
        2. 8.3.15.2 LVCMOS Output
      16. 8.3.16 Clock Output Interfacing and Termination
      17. 8.3.17 Glitchless Output Clock Start-Up
      18. 8.3.18 Output Auto-Mute During LOL
      19. 8.3.19 Output Synchronization (SYNC)
      20. 8.3.20 Zero-Delay Mode (ZDM)
      21. 8.3.21 DPLL Programmable Phase Delay
      22. 8.3.22 Time Elapsed Counter (TEC)
        1. 8.3.22.1 Configuring TEC Functionality
        2. 8.3.22.2 SPI as a Trigger Source
        3. 8.3.22.3 GPIO Pin as a TEC Trigger Source
          1. 8.3.22.3.1 An Example: Making a Time Elapsed Measurement Using TEC and GPIO1 as Trigger
        4. 8.3.22.4 TEC Timing
        5. 8.3.22.5 Other TEC Behavior
    4. 8.4 Device Functional Modes
      1. 8.4.1 DPLL Operating States
        1. 8.4.1.1 Free-Run
        2. 8.4.1.2 Lock Acquisition
        3. 8.4.1.3 DPLL Locked
        4. 8.4.1.4 Holdover
      2. 8.4.2 Digitally-Controlled Oscillator (DCO) Frequency and Phase Adjustment
        1. 8.4.2.1 DPLL DCO Control
        2. 8.4.2.2 DPLL DCO Relative Adjustment Frequency Step Size
        3. 8.4.2.3 APLL DCO Frequency Step Size
      3. 8.4.3 APLL Frequency Control
      4. 8.4.4 Device Start-Up
        1. 8.4.4.1 Device Power-On Reset (POR)
        2. 8.4.4.2 PLL Start-Up Sequence
        3. 8.4.4.3 Start-Up Options for Register Configuration
        4. 8.4.4.4 GPIO1 and SCS_ADD Functionalities
        5. 8.4.4.5 ROM Page Selection
        6. 8.4.4.6 ROM Detailed Description
        7. 8.4.4.7 EEPROM Overlay
    5. 8.5 Programming
      1. 8.5.1 Memory Overview
      2. 8.5.2 Interface and Control
        1. 8.5.2.1 Programming Through TICS Pro
        2. 8.5.2.2 SPI Serial Interface
        3. 8.5.2.3 I2C Serial Interface
      3. 8.5.3 General Register Programming Sequence
      4. 8.5.4 Steps to Program the EEPROM
        1. 8.5.4.1 Overview of the SRAM Programming Methods
        2. 8.5.4.2 EEPROM Programming With the Register Commit Method
        3. 8.5.4.3 EEPROM Programming With the Direct Writes Method or Mixed Method
        4. 8.5.4.4 Five MSBs of the I2C Address and the EEPROM Revision Number
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Device Start-Up Sequence
      2. 9.1.2 Power Down (PD#) Pin
      3. 9.1.3 Strap Pins for Start-Up
      4. 9.1.4 Pin States
      5. 9.1.5 ROM and EEPROM
      6. 9.1.6 Power Rail Sequencing, Power Supply Ramp Rate, and Mixing Supply Domains
        1. 9.1.6.1 Power-On Reset (POR) Circuit
        2. 9.1.6.2 Power Up From a Single-Supply Rail
        3. 9.1.6.3 Power Up From Split-Supply Rails
        4. 9.1.6.4 Non-Monotonic or Slow Power-Up Supply Ramp
      7. 9.1.7 Slow or Delayed XO Start-Up
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
    3. 9.3 Best Design Practices
    4. 9.4 Power Supply Recommendations
      1. 9.4.1 Power Supply Bypassing
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
      3. 9.5.3 Thermal Reliability
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
        1. 10.1.1.1 Clock Tree Architect Programming Software
        2. 10.1.1.2 Texas Instruments Clocks and Synthesizers (TICS) Pro Software
        3. 10.1.1.3 PLLatinum™ Simulation Tool
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Mechanical Data
    2.     PACKAGING INFORMATION
    3. 12.2 Tape and Reel Information

Package Options

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

8.4.4.1 Device Power-On Reset (POR)

Figure 8-41 shows the device power-on reset (POR) configuration sequence. POR occurs when the PD# pin is deasserted and reaches a logic high state. After POR, the serial control interface of choice (I2C or SPI) is selected. The LMK5C23208A supports preconfigured device settings from the factory preprogrammed internal ROM Detailed Description. A programmable EEPROM Overlay provides a flexible start-up of output clocks. Refer to Programming for after start-up programming details.

LMK5C23208A Device POR SequenceFigure 8-41 Device POR Sequence

After start-up, a global SWRST (R23[6]) restarts the device initialization sequence and APLL calibration state machine (see Figure 8-42). Issuing the global SWRST is recommended when modifying the APLL registers after POR to recalibrate all of the APLLs and re-align the output and SYSREF channel dividers.

When toggling the global SWRST, a disruption on the APLL output clocks can occur until the APLLs acquire lock again. An individual APLLx software reset (APLLx_SWRST) can be issued to avoid disturbing other APLL clocks. Use the APLLx_SWRST after bring-up when modifying the registers of the individual APLLx. For example, if only APLL1 registers are changed, then issue an APLL1_SWRST and only APLL1 outputs are briefly disrupted while APLL2 outputs remain undisturbed.

Issuing a SWRST is not required for the following cases:

  • When no register writes are performed after boot-up.
  • When only the XO input termination type, INx input termination type, output drivers (such as swing level or channel divider), GPIO pin, status, or DCO registers are modified after boot-up.
  • When programming the EEPROM.

Issuing a SWRST is recommended for the following cases:

  • When most of the register writes are modified through I2C or SPI (such as during device configuration after boot-up).
  • When the ZDM and SYSREF registers are configured. Not required if only changing the SYSREF divider value.
  • When the APLLx registers are modified and a brief interruption on all of the APLLx clocks is not an issue.

Issuing an individual APLLx_SWRST is recommended for the following cases:

  • When the device has been configured with the desired registers and only APLLx registers need to be modified without disturbing the other APLL output clocks.