SNAS722A December   2017  – October 2018 LMK61E07

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Pinout and Simplified Block Diagram
      1.      Device Images
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions
  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 - Power Supply
    6. 6.6  LVPECL Output Characteristics
    7. 6.7  LVDS Output Characteristics
    8. 6.8  HCSL Output Characteristics
    9. 6.9  Frequency Tolerance Characteristics
    10. 6.10 Frequency Margining Characteristics
    11. 6.11 Power-On Reset Characteristics (VDD)
    12. 6.12 I2C-Compatible Interface Characteristics (SDA, SCL)
    13. 6.13 PSRR Characteristics
    14. 6.14 Other Characteristics
    15. 6.15 PLL Clock Output Jitter Characteristics
    16. 6.16 Typical 156.25-MHz Output Phase Noise Characteristics
    17. 6.17 Typical 161.1328125 MHz Output Phase Noise Characteristics
    18. 6.18 Additional Reliability and Qualification
    19. 6.19 Typical Characteristics
  7. Parameter Measurement Information
    1. 7.1 Device Output Configurations
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Device Block-Level Description
      2. 8.3.2  Device Configuration Control
      3. 8.3.3  Register File Reference Convention
      4. 8.3.4  Configuring the PLL
      5. 8.3.5  Integrated Oscillator
      6. 8.3.6  Reference Divider and Doubler
      7. 8.3.7  Phase Frequency Detector
      8. 8.3.8  Feedback Divider (N)
      9. 8.3.9  Fractional Engine
      10. 8.3.10 Charge Pump
      11. 8.3.11 Loop Filter
      12. 8.3.12 VCO Calibration
      13. 8.3.13 High-Speed Output Divider
      14. 8.3.14 High-Speed Clock Output
      15. 8.3.15 Device Status
        1. 8.3.15.1 Loss of Lock
    4. 8.4 Device Functional Modes
      1. 8.4.1 Interface and Control
      2. 8.4.2 DCXO Mode and Frequency Margining
        1. 8.4.2.1 DCXO Mode
        2. 8.4.2.2 Fine Frequency Margining
        3. 8.4.2.3 Coarse Frequency Margining
    5. 8.5 Programming
      1. 8.5.1 I2C Serial Interface
      2. 8.5.2 Block Register Write
      3. 8.5.3 Block Register Read
      4. 8.5.4 Write SRAM
      5. 8.5.5 Write EEPROM
      6. 8.5.6 Read SRAM
      7. 8.5.7 Read EEPROM
    6. 8.6 Register Maps
      1. 8.6.1 Register Descriptions
        1. 8.6.1.1  VNDRID_BY1 Register; R0
        2. 8.6.1.2  VNDRID_BY0 Register; R1
        3. 8.6.1.3  PRODID Register; R2
        4. 8.6.1.4  REVID Register; R3
        5. 8.6.1.5  SLAVEADR Register; R8
        6. 8.6.1.6  EEREV Register; R9
        7. 8.6.1.7  DEV_CTL Register; R10
        8. 8.6.1.8  XO_CAPCTRL_BY1 Register; R16
        9. 8.6.1.9  XO_CAPCTRL_BY0 Register; R17
        10. 8.6.1.10 DIFFCTL Register; R21
        11. 8.6.1.11 OUTDIV_BY1 Register; R22
        12. 8.6.1.12 OUTDIV_BY0 Register; R23
        13. 8.6.1.13 RDIVCMOSCTL Register; R24
        14. 8.6.1.14 PLL_NDIV_BY1 Register; R25
        15. 8.6.1.15 PLL_NDIV_BY0 Register; R26
        16. 8.6.1.16 PLL_FRACNUM_BY2 Register; R27
        17. 8.6.1.17 PLL_FRACNUM_BY1 Register; R28
        18. 8.6.1.18 PLL_FRACNUM_BY0 Register; R29
        19. 8.6.1.19 PLL_FRACDEN_BY2 Register; R30
        20. 8.6.1.20 PLL_FRACDEN_BY1 Register; R31
        21. 8.6.1.21 PLL_FRACDEN_BY0 Register; R32
        22. 8.6.1.22 PLL_MASHCTRL Register; R33
        23. 8.6.1.23 PLL_CTRL0 Register; R34
        24. 8.6.1.24 PLL_CTRL1 Register; R35
        25. 8.6.1.25 PLL_LF_R2 Register; R36
        26. 8.6.1.26 PLL_LF_C1 Register; R37
        27. 8.6.1.27 PLL_LF_R3 Register; R38
        28. 8.6.1.28 PLL_LF_C3 Register; R39
        29. 8.6.1.29 PLL_CALCTRL Register; R42
        30. 8.6.1.30 NVMSCRC Register; R47
        31. 8.6.1.31 NVMCNT Register; R48
        32. 8.6.1.32 NVMCTL Register; R49
        33. 8.6.1.33 MEMADR Register; R51
        34. 8.6.1.34 NVMDAT Register; R52
        35. 8.6.1.35 RAMDAT Register; R53
        36. 8.6.1.36 NVMUNLK Register; R56
        37. 8.6.1.37 INT_LIVE Register; R66
        38. 8.6.1.38 SWRST Register; R72
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 PLL Loop Filter Design
        2. 9.2.2.2 Spur Mitigation Techniques
          1. 9.2.2.2.1 Phase Detection Spur
          2. 9.2.2.2.2 Integer Boundary Fractional Spur
          3. 9.2.2.2.3 Primary Fractional Spur
          4. 9.2.2.2.4 Sub-Fractional Spur
        3. 9.2.2.3 Device Programming
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Ensured Thermal Reliability
      2. 11.1.2 Best Practices for Signal Integrity
      3. 11.1.3 Recommended Solder Reflow Profile
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • SIA|6
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Detailed Design Procedure

This design procedure will give a quick outline of the process of configuring the LMK61E07 in the above use case. Typically, the easiest approach to configuring the PLL is to start with the desired output frequency and work backwards.

  1. VCO Frequency Selection
    • The first step is to calculate the possible VCO frequencies given the required output frequency of 70.656 MHz. The LMK61E07 output divider that can be set from /5 to /511. The VCO can output frequencies from 4.6 GHz to 5.6 GHz. Therefore, the output frequency multiplied by the total divide value must fall within this range.
    • To determine the boundary of the total divide value, we can divide the VCO frequency limits by the output frequency, resulting in a range of 65.1 to 79.3. Any output divider value within this range will result in a valid VCO frequency. A few possible divider combinations and the resulting VCO frequencies are listed in columns 1 and 2, respectively, of Table 3 below.
  2. Input Divider and Doubler/Phase Detector Frequency Configuration
    • The next step is to set the reference divider and doubler in the reference frequency path to the PLL. The reference divider can be set to /1 or /4, and the doubler can be set to x1 or x2. The main trade-off is that a higher phase detector frequency will result in better output phase noise performance and a lower phase detector frequency will result in a finer output frequency step size when adjusting the feedback divider numerator in DCXO mode.
    • In the DSL application, a finer step size is desired so the reference divider will be set to /4 and the doubler to x1 to minimize the phase detector frequency. The phase detector frequency can then be calculated by multiplying and dividing the reference frequency of 50 MHz by those values, resulting in 12.5 MHz.
    • Note that in some applications, a trade-off in step size to obtain better phase noise performance is acceptable. In that case the design procedure can be continued, substituting the relevant reference divider and doubler configuration and phase detector frequency.
  3. Feedback Divider Selection
    • The possible feedback divider values can then be calculated by dividing the VCO frequency by the phase detector frequency. The possible values are listed in column 3 of Table 3.
    • Glitch-less frequency margining in DCXO mode is achieved by adjusting the numerator of the feedback divider without changing the integer value of the divider, which could cause a frequency glitch. Therefore, the output frequency tuning range is limited by which VCO frequency and feedback divider we select out of the valid combinations. To obtain as equal of a tuning range above and below the nominal output frequency as possible, a feedback divider value with fractional portion as close to 1/2 as possible should be chosen.
    • The VCO frequency of 5369.856 MHz results in a feedback divider of 429.58848, which has a fractional portion closest to 1/2. The decimal converted to a fraction is 429+58848/100000. To minimize step size, the fraction can be converted to the maximum equivalent fraction of 2412768/4100000 as limited by the maximum denominator of 4194303.
  4. Frequency Margining
    • With the device configured to output the nominal frequency of 70.656 MHz, the numerator can be adjusted over I2C to tune the output frequency.
    • Using equation 3 in Configuring the PLL, the step size of this configuration can be calculated to be approximately 4x10–8 MHz or 0.58 ppb.
    • The maximum and minimum tuning range limits can be determined by calculating the maximum shift in frequency from nominal without changing the integer portion of the feedback divider (including setting the numerator to zero or equal to the denominator). In this case, the limits are a maximum of +955 ppm and a minimum of –1365 ppm from nominal.

Table 3. PLL Configuration Options

1. EXAMPLE OUTPUT DIVIDER VALUES 2. POSSIBLE VCO FREQUENCIES (MHz) 3. FEEDBACK DIVIDER WITH PDF=12.5 MHz 4. EQUIVALENT FRACTIONAL FEEDBACK DIVIDER VALUES
68 4804.608 384.36864 384+1511424/4100000
70 4945.92 395.6736 395+2822384/4190000
72 5087.232 406.97856 406+4012096/4100000
75 5299.2 423.936 423+3925584/4194000
76 5369.856 429.58848 429+2412768/4100000