SNAS689A October   2017  – July 2019 LMK04228

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Schematic
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  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 SPI Interface Timing
    7. 7.7 Timing Diagram
  8. 8 Parameter Measurement Information
    1. 8.1 Charge Pump Current Specification Definitions
      1. 8.1.1 Charge Pump Output Current Magnitude Variation vs. Charge Pump Output Voltage
      2. 8.1.2 Charge Pump Sink Current vs. Charge Pump Output Source Current Mismatch
      3. 8.1.3 Charge Pump Output Current Magnitude Variation vs. Ambient Temperature
    2. 8.2 Differential Voltage Measurement Terminology
  9. 9 Detailed Description
    1. 9.1 Overview
      1. 9.1.1 Jitter Cleaning
      2. 9.1.2 JEDEC JESD204B Support
      3. 9.1.3 Three PLL1 Redundant Reference Inputs (CLKin0/CLKin0*, CLKin1/CLKin1*, and CLKin2/CLKin2*)
      4. 9.1.4 VCXO- and Crystal-Buffered Output
      5. 9.1.5 Frequency Holdover
      6. 9.1.6 PLL2 Integrated Loop Filter Poles
      7. 9.1.7 Internal VCOs
      8. 9.1.8 Clock Distribution
        1. 9.1.8.1 Device Clock Divider
        2. 9.1.8.2 SYSREF Clock Divider
        3. 9.1.8.3 Device Clock Delay
        4. 9.1.8.4 SYSREF Delay
        5. 9.1.8.5 Programmable Output Formats
        6. 9.1.8.6 Clock Output Synchronization
      9. 9.1.9 Status Pins
    2. 9.2 Functional Block Diagrams
    3. 9.3 Feature Description
      1. 9.3.1 SYNC/SYSREF
      2. 9.3.2 JEDEC JESD204B
        1. 9.3.2.1 How to Enable SYSREF
          1. 9.3.2.1.1 Setup of SYSREF Example
          2. 9.3.2.1.2 SYSREF_CLR
        2. 9.3.2.2 SYSREF Modes
          1. 9.3.2.2.1 SYSREF Pulser
          2. 9.3.2.2.2 Continuous SYSREF
          3. 9.3.2.2.3 SYSREF Request
      3. 9.3.3 Digital Delay
        1. 9.3.3.1 Fixed Digital Delay
          1. 9.3.3.1.1 Fixed Digital Delay Example
      4. 9.3.4 SYSREF to Device Clock Alignment
      5. 9.3.5 Input Clock Switching
        1. 9.3.5.1 Input Clock Switching - Manual Mode
        2. 9.3.5.2 Input Clock Switching - Pin Select Mode
          1. 9.3.5.2.1 Configuring Pin Select Mode
        3. 9.3.5.3 Input Clock Switching - Automatic Mode
          1. 9.3.5.3.1 Starting Active Clock
      6. 9.3.6 Digital Lock Detect
        1. 9.3.6.1 Calculating Digital Lock Detect Frequency Accuracy
      7. 9.3.7 Holdover
        1. 9.3.7.1 Enable Holdover
          1. 9.3.7.1.1 Fixed (Manual) CPout1 Holdover Mode
          2. 9.3.7.1.2 Tracked CPout1 Holdover Mode
        2. 9.3.7.2 During Holdover
        3. 9.3.7.3 Exiting Holdover
        4. 9.3.7.4 Holdover Frequency Accuracy and DAC Performance
        5. 9.3.7.5 Holdover Mode - Automatic Exit of Holdover
    4. 9.4 Programming
      1. 9.4.1 Recommended Programming Sequence
        1. 9.4.1.1 SPI LOCK
        2. 9.4.1.2 SYSREF_CLR
    5. 9.5 Register Maps
      1. 9.5.1 Register Map for Device Programming
      2. 9.5.2 Device Register Descriptions
        1. 9.5.2.1 System Functions
          1. 9.5.2.1.1 RESET, SPI_3WIRE_DIS
          2. 9.5.2.1.2 POWERDOWN
          3. 9.5.2.1.3 ID_DEVICE_TYPE
          4. 9.5.2.1.4 ID_PROD[15:8], ID_PROD
          5. 9.5.2.1.5 ID_MASKREV
          6. 9.5.2.1.6 ID_VNDR[15:8], ID_VNDR
        2. 9.5.2.2 (0x100 - 0x138) Device Clock and SYSREF Clock Output Controls
          1. 9.5.2.2.1 CLKoutX_Y_ODL, CLKoutX_Y_IDL, DCLKoutX_DIV
          2. 9.5.2.2.2 DCLKoutX_DDLY_CNTH, DCLKoutX_DDLY_CNTL
          3. 9.5.2.2.3 DCLKoutX_ADLY, DCLKoutX_ADLY_MUX, DCLKout_MUX
          4. 9.5.2.2.4 DCLKoutX_HS, SDCLKoutY_MUX, SDCLKoutY_DDLY, SDCLKoutY_HS
          5. 9.5.2.2.5 SDCLKoutY_ADLY_EN, SDCLKoutY_ADLY
          6. 9.5.2.2.6 DCLKoutX_DDLY_PD, DCLKout_ADLY_PD, DCLKoutX_Y_PD, SDCLKoutY_DIS_MODE, SDCLKoutY_PD
          7. 9.5.2.2.7 SDCLKoutY_POL, SDCLKoutY_FMT, DCLKoutX_POL, DCLKoutX_FMT
        3. 9.5.2.3 SYSREF, SYNC, and Device Config
          1. 9.5.2.3.1 VCO_MUX, OSCout_FMT
          2. 9.5.2.3.2 SYSREF_CLKin0_MUX, SYSREF_MUX
          3. 9.5.2.3.3 SYSREF_DIV[12:8], SYSREF_DIV[7:0]
          4. 9.5.2.3.4 SYSREF_DDLY[12:8], SYSREF_DDLY[7:0]
          5. 9.5.2.3.5 SYSREF_PULSE_CNT
          6. 9.5.2.3.6 PLL1_PD, VCO_LDO_PD, VCO_PD, OSCin_PD, SYSREF_GBL_PD, SYSREF_PD, SYSREF_DDLY_PD, SYSREF_PLSR_PD
          7. 9.5.2.3.7 SYSREF_CLR, SYNC_1SHOT_EN, SYNC_POL, SYNC_EN, SYNC_PLL2_DLD, SYNC_PLL1_DLD, SYNC_MODE
          8. 9.5.2.3.8 SYNC_DISSYSREF, SYNC_DISX
          9. 9.5.2.3.9 Fixed Register
        4. 9.5.2.4 (0x146 - 0x149) CLKin Control
          1. 9.5.2.4.1 CLKin2_EN, CLKin1_EN, CLKin0_EN, CLKin2_TYPE, CLKin1_TYPE, CLKin0_TYPE
          2. 9.5.2.4.2 CLKin_SEL_POL, CLKin_SEL_MODE, CLKin1_OUT_MUX, CLKin0_OUT_MUX
          3. 9.5.2.4.3 CLKin_SEL0_MUX, CLKin_SEL0_TYPE
          4. 9.5.2.4.4 SDIO_RDBK_TYPE, CLKin_SEL1_MUX, CLKin_SEL1_TYPE
        5. 9.5.2.5 RESET_MUX, RESET_TYPE
        6. 9.5.2.6 (0x14B - 0x152) Holdover
          1. 9.5.2.6.1 LOS_TIMEOUT, LOS_EN, TRACK_EN, HOLDOVER_FORCE, MAN_DAC_EN, MAN_DAC[9:8]
          2. 9.5.2.6.2 MAN_DAC[9:8], MAN_DAC[7:0]
          3. 9.5.2.6.3 DAC_TRIP_LOW
          4. 9.5.2.6.4 DAC_CLK_MULT, DAC_TRIP_HIGH
          5. 9.5.2.6.5 DAC_CLK_CNTR
          6. 9.5.2.6.6 CLKin_OVERRIDE, HOLDOVER_PLL1_DET, HOLDOVER_LOS_DET, HOLDOVER_VTUNE_DET, HOLDOVER_HITLESS_SWITCH, HOLDOVER_EN
          7. 9.5.2.6.7 HOLDOVER_DLD_CNT[13:8], HOLDOVER_DLD_CNT[7:0]
        7. 9.5.2.7 (0x153 - 0x15F) PLL1 Configuration
          1. 9.5.2.7.1 CLKin0_R[9:8], CLKin0_R[7:0]
          2. 9.5.2.7.2 CLKin1_R[9:8], CLKin1_R[7:0]
          3. 9.5.2.7.3 CLKin2_R[9:8], CLKin2_R[7:0]
          4. 9.5.2.7.4 PLL1_N
          5. 9.5.2.7.5 PLL1_WND_SIZE, PLL1_CP_TRI, PLL1_CP_POL, PLL1_CP_GAIN
          6. 9.5.2.7.6 PLL1_DLD_CNT[13:8], PLL1_DLD_CNT[7:0]
          7. 9.5.2.7.7 PLL1_LD_MUX, PLL1_LD_TYPE
        8. 9.5.2.8 (0x160 - 0x16E) PLL2 Configuration
          1. 9.5.2.8.1 PLL2_R[4:0]
          2. 9.5.2.8.2 PLL2_P, OSCin_FREQ, PLL2_XTAL_EN, PLL2_REF_2X_EN
          3. 9.5.2.8.3 PLL2_FCAL_DIS
          4. 9.5.2.8.4 PLL2_N
          5. 9.5.2.8.5 PLL2_WND_SIZE, PLL2_CP_GAIN, PLL2_CP_POL, PLL2_CP_TRI
          6. 9.5.2.8.6 SYSREF_REQ_EN, PLL2_DLD_CNT
          7. 9.5.2.8.7 PLL2_LF_R4, PLL2_LF_R3
          8. 9.5.2.8.8 PLL2_LF_C4, PLL2_LF_C3
          9. 9.5.2.8.9 PLL2_LD_MUX, PLL2_LD_TYPE
        9. 9.5.2.9 (0x16F - 0x1FFF) Misc Registers
          1. 9.5.2.9.1  Fixed Register
          2. 9.5.2.9.2  Fixed Register
          3. 9.5.2.9.3  PLL2_PRE_PD, PLL2_PD
          4. 9.5.2.9.4  OPT_REG_1
          5. 9.5.2.9.5  OPT_REG_2
          6. 9.5.2.9.6  RB_PLL1_LD_LOST, RB_PLL1_LD, CLR_PLL1_LD_LOST
          7. 9.5.2.9.7  RB_PLL2_LD_LOST, RB_PLL2_LD, CLR_PLL2_LD_LOST
          8. 9.5.2.9.8  RB_DAC_VALUE(MSB), RB_CLKinX_SEL, RB_CLKinX_LOS
          9. 9.5.2.9.9  RB_DAC_VALUE
          10. 9.5.2.9.10 RB_HOLDOVER
          11. 9.5.2.9.11 SPI_LOCK
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Digital Lock Detect Frequency Accuracy
        1. 10.1.1.1 Minimum Lock Time Calculation Example
      2. 10.1.2 Driving CLKin AND OSCin Inputs
        1. 10.1.2.1 Driving CLKin PINS With a Differential Source
        2. 10.1.2.2 Driving CLKin Pins With a Single-Ended Source
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Device Programming
    3. 10.3 Do's and Don'ts
      1. 10.3.1 Pin Connection Recommendations
  11. 11Power Supply Recommendations
    1. 11.1 Current Consumption / Power Dissipation Calculations
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Thermal Management
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 TICS Pro
    2. 13.2 Community Resources
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

10.1.1 Digital Lock Detect Frequency Accuracy

The digital lock detect circuit is used to determine PLL1 locked, PLL2 locked, and holdover exit events. A window size and lock count register are programmed to set a ppm frequency accuracy of reference to feedback signals of the PLL for each event to occur. When a PLL digital lock event occurs, the corresponding PLL digital lock detect is asserted true. When the holdover exit event occurs, the device will exit holdover mode.

EVENT PLL WINDOW SIZE LOCK COUNT
PLL1 Locked PLL1 PLL1_WND_SIZE PLL1_DLD_CNT
PLL2 Locked PLL2 PLL2_WND_SIZE PLL2_DLD_CNT
Holdover Exit PLL1 PLL1_WND_SIZE HOLDOVER_DLD_CNT

For a digital lock detect event to occur there must be a lock count number of phase detector cycles of PLLX during which the time/phase error of the PLLX_R reference and PLLX_N feedback signal edges are within the user programmable window size. Because there must be at least lock count phase detector events before a lock event occurs, a minimum digital lock event time can be calculated as lock count / fPDX where X = 1 for PLL1 or 2 for PLL2.

By using Equation 3, values for a lock count and window size can be chosen to set the frequency accuracy required by the system in ppm before the digital lock detect event occurs:

Equation 3. LMK04228 ai_q_digitallockdet.gif

The effect of the lock count value is that it shortens the effective lock window size by dividing the window size by lock count.

If at any time the PLLX_R reference and PLLX_N feedback signals are outside the time window set by window size, then the lock count value is reset to 0.

NOTE

In cases where the period of the phase detector frequency approaches the value of the default PLL1_WND_SIZE increment (40 ns), the lock detect circuit will not function with the default value of PLL1_WND_SIZE. For phase detector frequencies at or above 25 MHz, TI recommends setting PLL1_WND_SIZE to 0x02 (19 ns) or a smaller value.