SNAS692A January   2017  – May 2017 LMK61E0M

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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  3.3-V LVCMOS Output Characteristics
    7. 6.7  OE Input Characteristics
    8. 6.8  ADD Input 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 Other Characteristics
    14. 6.14 PLL Clock Output Jitter Characteristics
    15. 6.15 Additional Reliability and Qualification
    16. 6.16 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Device Output Configurations
  8. 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 CMOSCTL Register; R20
        11. 8.6.1.11 DIFFCTL Register; R21
        12. 8.6.1.12 OUTDIV_BY1 Register; R22
        13. 8.6.1.13 OUTDIV_BY0 Register; R23
        14. 8.6.1.14 RDIVCMOSCTL Register; R24
        15. 8.6.1.15 PLL_NDIV_BY1 Register; R25
        16. 8.6.1.16 PLL_NDIV_BY0 Register; R26
        17. 8.6.1.17 PLL_FRACNUM_BY2 Register; R27
        18. 8.6.1.18 PLL_FRACNUM_BY1 Register; R28
        19. 8.6.1.19 PLL_FRACNUM_BY0 Register; R29
        20. 8.6.1.20 PLL_FRACDEN_BY2 Register; R30
        21. 8.6.1.21 PLL_FRACDEN_BY1 Register; R31
        22. 8.6.1.22 PLL_FRACDEN_BY0 Register; R32
        23. 8.6.1.23 PLL_MASHCTRL Register; R33
        24. 8.6.1.24 PLL_CTRL0 Register; R34
        25. 8.6.1.25 PLL_CTRL1 Register; R35
        26. 8.6.1.26 PLL_LF_R2 Register; R36
        27. 8.6.1.27 PLL_LF_C1 Register; R37
        28. 8.6.1.28 PLL_LF_R3 Register; R38
        29. 8.6.1.29 PLL_LF_C3 Register; R39
        30. 8.6.1.30 PLL_CALCTRL Register; R42
        31. 8.6.1.31 NVMSCRC Register; R47
        32. 8.6.1.32 NVMCNT Register; R48
        33. 8.6.1.33 NVMCTL Register; R49
        34. 8.6.1.34 MEMADR Register; R51
        35. 8.6.1.35 NVMDAT Register; R52
        36. 8.6.1.36 RAMDAT Register; R53
        37. 8.6.1.37 NVMUNLK Register; R56
        38. 8.6.1.38 INT_LIVE Register; R66
        39. 8.6.1.39 SWRST Register; R72
  9. 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

11 Layout

11.1 Layout Guidelines

Ensured Thermal Reliability, Best Practices for Signal Integrity and Recommended Solder Reflow Profile provide recommendations for board layout, solder reflow profile and power supply bypassing when using LMK61E0 to ensure good thermal and electrical performance and overall signal integrity of entire system.

11.1.1 Ensured Thermal Reliability

The LMK61E0 is a high performance device. Therefore careful attention must be paid to device configuration and printed-circuit board (PCB) layout with respect to power consumption. The ground pin needs to be connected to the ground plane of the PCB through three vias or more, as shown in Figure 16, to maximize thermal dissipation out of the package.

Equation 4 describes the relationship between the PCB temperature around the LMK61E0 and its junction temperature.

Equation 4. TB = TJ – ΨJB * P

where

  • TB: PCB temperature around the LMK61E0
  • TJ: Junction temperature of LMK61E0
  • ΨJB: Junction-to-board thermal resistance parameter of LMK61E0 (36.7°C/W without airflow)
  • P: On-chip power dissipation of LMK61E0

To ensure that the maximum junction temperature of LMK61E0 is below 115°C, it can be calculated that the maximum PCB temperature without airflow should be at 93°C or below when the device is optimized for best performance resulting in maximum on-chip power dissipation of 0.6 W.

11.1.2 Best Practices for Signal Integrity

For best electrical performance and signal integrity of entire system with LMK61E0, TI recommends routing vias into decoupling capacitors and then into the LMK61E0. TI also recommends increasing the via count and width of the traces wherever possible. These steps ensure lowest impedance and shortest path for high-frequency current flow. Figure 16 shows the layout recommendation for LMK61E0.

11.1.3 Recommended Solder Reflow Profile

TI also recommends following the solder paste supplier's recommendations to optimize flux activity and to achieve proper melting temperatures of the alloy within the guidelines of J-STD-20. It is preferable for the LMK61E0 to be processed with the lowest peak temperature possible while also remaining below the components peak temperature rating as listed on the MSL label. The exact temperature profile would depend on several factors including maximum peak temperature for the component as rated on the MSL label, Board thickness, PCB material type, PCB geometries, component locations, sizes, densities within PCB, as well solder manufactures recommended profile, and capability of the reflow equipment to as confirmed by the SMT assembly operation.

11.2 Layout Example

LMK61E0M layout_example_snas674.png Figure 16. LMK61E0 Layout Recommendation for Power Supply and Ground