SNAS788C November   2019  – March 2022 LMX2694-SEP

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
    6. 6.6 Timing Requirements
    7. 6.7 Timing Diagrams
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Reference Oscillator Input
      2. 7.3.2  Reference Path
        1. 7.3.2.1 OSCIN Doubler (OSC_2X)
        2. 7.3.2.2 Pre-R Divider (PLL_R_PRE)
        3. 7.3.2.3 Post-R Divider (PLL_R)
      3. 7.3.3  State Machine Clock
      4. 7.3.4  PLL Phase Detector and Charge Pump
      5. 7.3.5  N Divider and Fractional Circuitry
      6. 7.3.6  MUXOUT Pin
        1. 7.3.6.1 Serial Data Output for Readback
        2. 7.3.6.2 Lock Detect Indicator Set as Type “VCOCal”
        3. 7.3.6.3 Lock Detect Indicator Set as Type “Vtune and VCOCal”
      7. 7.3.7  VCO (Voltage-Controlled Oscillator)
        1. 7.3.7.1 VCO Calibration
        2. 7.3.7.2 Determining the VCO Gain
      8. 7.3.8  Channel Divider
      9. 7.3.9  Output Buffer
      10. 7.3.10 Powerdown Modes
      11. 7.3.11 Treatment of Unused Pins
      12. 7.3.12 Phase Synchronization
        1. 7.3.12.1 General Concept
        2. 7.3.12.2 Categories of Applications for SYNC
        3. 7.3.12.3 Procedure for Using SYNC
        4. 7.3.12.4 SYNC Input Pin
      13. 7.3.13 Phase Adjust
      14. 7.3.14 Fine Adjustments for Phase Adjust and Phase SYNC
      15. 7.3.15 SYSREF
        1. 7.3.15.1 Programmable Fields
        2. 7.3.15.2 Input and Output Pin Formats
          1. 7.3.15.2.1 SYSREF Output Format
        3. 7.3.15.3 SYSREF Examples
        4. 7.3.15.4 SYSREF Procedure
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
      1. 7.5.1 Recommended Initial Power-Up Sequence
      2. 7.5.2 Recommended Sequence for Changing Frequencies
    6. 7.6 Register Maps
      1. 7.6.1   R0 Register (Offset = 0x0) [reset = 0x200C]
      2. 7.6.2   R1 Register (Offset = 0x1) [reset = 0x80C]
      3. 7.6.3   R2 Register (Offset = 0x2) [reset = 0x500]
      4. 7.6.4   R3 Register (Offset = 0x3) [reset = 0x642]
      5. 7.6.5   R4 Register (Offset = 0x4) [reset = 0xA43]
      6. 7.6.6   R5 Register (Offset = 0x5) [reset = 0xC8]
      7. 7.6.7   R6 Register (Offset = 0x6) [reset = 0xC802]
      8. 7.6.8   R7 Register (Offset = 0x7) [reset = 0xB2]
      9. 7.6.9   R8 Register (Offset = 0x8) [reset = 0x2000]
      10. 7.6.10  R9 Register (Offset = 0x9) [reset = 0x604]
      11. 7.6.11  R10 Register (Offset = 0xA) [reset = 0x10F8]
      12. 7.6.12  R11 Register (Offset = 0xB) [reset = 0x18]
      13. 7.6.13  R12 Register (Offset = 0xC) [reset = 0x5001]
      14. 7.6.14  R13 Register (Offset = 0xD) [reset = 0x4000]
      15. 7.6.15  R14 Register (Offset = 0xE) [reset = 0x1E70]
      16. 7.6.16  R15 Register (Offset = 0xF) [reset = 0x64F]
      17. 7.6.17  R16 Register (Offset = 0x10) [reset = 0x80]
      18. 7.6.18  R17 Register (Offset = 0x11) [reset = 0x96]
      19. 7.6.19  R18 Register (Offset = 0x12) [reset = 0x64]
      20. 7.6.20  R19 Register (Offset = 0x13) [reset = 0x27B7]
      21. 7.6.21  R20 Register (Offset = 0x14) [reset = 0x3048]
      22. 7.6.22  R21 Register (Offset = 0x15) [reset = 0x401]
      23. 7.6.23  R22 Register (Offset = 0x16) [reset = 0x1]
      24. 7.6.24  R23 Register (Offset = 0x17) [reset = 0x7C]
      25. 7.6.25  R24 Register (Offset = 0x18) [reset = 0x71A]
      26. 7.6.26  R25 Register (Offset = 0x19) [reset = 0x624]
      27. 7.6.27  R26 Register (Offset = 0x1A) [reset = 0xDB0]
      28. 7.6.28  R27 Register (Offset = 0x1B) [reset = 0x2]
      29. 7.6.29  R28 Register (Offset = 0x1C) [reset = 0x488]
      30. 7.6.30  R29 Register (Offset = 0x1D) [reset = 0x318C]
      31. 7.6.31  R30 Register (Offset = 0x1E) [reset = 0x318C]
      32. 7.6.32  R31 Register (Offset = 0x1F) [reset = 0xC3EC]
      33. 7.6.33  R32 Register (Offset = 0x20) [reset = 0x393]
      34. 7.6.34  R33 Register (Offset = 0x21) [reset = 0x1E21]
      35. 7.6.35  R34 Register (Offset = 0x22) [reset = 0x10]
      36. 7.6.36  R35 Register (Offset = 0x23) [reset = 0x4]
      37. 7.6.37  R36 Register (Offset = 0x24) [reset = 0x70]
      38. 7.6.38  R37 Register (Offset = 0x25) [reset = 0x205]
      39. 7.6.39  R38 Register (Offset = 0x26) [reset = 0xFFFF]
      40. 7.6.40  R39 Register (Offset = 0x27) [reset = 0xFFFF]
      41. 7.6.41  R40 Register (Offset = 0x28) [reset = 0x0]
      42. 7.6.42  R41 Register (Offset = 0x29) [reset = 0x0]
      43. 7.6.43  R42 Register (Offset = 0x2A) [reset = 0x0]
      44. 7.6.44  R43 Register (Offset = 0x2B) [reset = 0x0]
      45. 7.6.45  R44 Register (Offset = 0x2C) [reset = 0x22A2]
      46. 7.6.46  R45 Register (Offset = 0x2D) [reset = 0xC622]
      47. 7.6.47  R46 Register (Offset = 0x2E) [reset = 0x7F0]
      48. 7.6.48  R47 Register (Offset = 0x2F) [reset = 0x300]
      49. 7.6.49  R48 Register (Offset = 0x30) [reset = 0x3E0]
      50. 7.6.50  R49 Register (Offset = 0x31) [reset = 0x4180]
      51. 7.6.51  R50 Register (Offset = 0x32) [reset = 0x80]
      52. 7.6.52  R51 Register (Offset = 0x33) [reset = 0x80]
      53. 7.6.53  R52 Register (Offset = 0x34) [reset = 0x420]
      54. 7.6.54  R53 Register (Offset = 0x35) [reset = 0x0]
      55. 7.6.55  R54 Register (Offset = 0x36) [reset = 0x0]
      56. 7.6.56  R55 Register (Offset = 0x37) [reset = 0x0]
      57. 7.6.57  R56 Register (Offset = 0x38) [reset = 0x0]
      58. 7.6.58  R57 Register (Offset = 0x39) [reset = 0x0]
      59. 7.6.59  R58 Register (Offset = 0x3A) [reset = 0x8001]
      60. 7.6.60  R59 Register (Offset = 0x3B) [reset = 0x1]
      61. 7.6.61  R60 Register (Offset = 0x3C) [reset = 0x3E8]
      62. 7.6.62  R61 Register (Offset = 0x3D) [reset = 0xA8]
      63. 7.6.63  R62 Register (Offset = 0x3E) [reset = 0xAE]
      64. 7.6.64  R63 Register (Offset = 0x3F) [reset = 0x0]
      65. 7.6.65  R64 Register (Offset = 0x40) [reset = 0x1388]
      66. 7.6.66  R65 Register (Offset = 0x41) [reset = 0x0]
      67. 7.6.67  R66 Register (Offset = 0x42) [reset = 0x140]
      68. 7.6.68  R67 Register (Offset = 0x43) [reset = 0x0]
      69. 7.6.69  R68 Register (Offset = 0x44) [reset = 0x3E8]
      70. 7.6.70  R69 Register (Offset = 0x45) [reset = 0x0]
      71. 7.6.71  R70 Register (Offset = 0x46) [reset = 0xC350]
      72. 7.6.72  R71 Register (Offset = 0x47) [reset = 0x80]
      73. 7.6.73  R72 Register (Offset = 0x48) [reset = 0x1]
      74. 7.6.74  R73 Register (Offset = 0x49) [reset = 0x3F]
      75. 7.6.75  R74 Register (Offset = 0x4A) [reset = 0x0]
      76. 7.6.76  R75 Register (Offset = 0x4B) [reset = 0x800]
      77. 7.6.77  R76 Register (Offset = 0x4C) [reset = 0xC]
      78. 7.6.78  R77 Register (Offset = 0x4D) [reset = 0x0]
      79. 7.6.79  R78 Register (Offset = 0x4E) [reset = 0x64]
      80. 7.6.80  R79 Register (Offset = 0x4F) [reset = 0x0]
      81. 7.6.81  R80 Register (Offset = 0x50) [reset = 0x0]
      82. 7.6.82  R81 Register (Offset = 0x51) [reset = 0x0]
      83. 7.6.83  R82 Register (Offset = 0x52) [reset = 0x0]
      84. 7.6.84  R83 Register (Offset = 0x53) [reset = 0x0]
      85. 7.6.85  R84 Register (Offset = 0x54) [reset = 0x0]
      86. 7.6.86  R85 Register (Offset = 0x55) [reset = 0x0]
      87. 7.6.87  R86 Register (Offset = 0x56) [reset = 0x0]
      88. 7.6.88  R87 Register (Offset = 0x57) [reset = 0x0]
      89. 7.6.89  R88 Register (Offset = 0x58) [reset = 0x0]
      90. 7.6.90  R89 Register (Offset = 0x59) [reset = 0x0]
      91. 7.6.91  R90 Register (Offset = 0x5A) [reset = 0x0]
      92. 7.6.92  R91 Register (Offset = 0x5B) [reset = 0x0]
      93. 7.6.93  R92 Register (Offset = 0x5C) [reset = 0x0]
      94. 7.6.94  R93 Register (Offset = 0x5D) [reset = 0x0]
      95. 7.6.95  R94 Register (Offset = 0x5E) [reset = 0x0]
      96. 7.6.96  R95 Register (Offset = 0x5F) [reset = 0x0]
      97. 7.6.97  R96 Register (Offset = 0x60) [reset = 0x0]
      98. 7.6.98  R97 Register (Offset = 0x61) [reset = 0x0]
      99. 7.6.99  R98 Register (Offset = 0x62) [reset = 0x0]
      100. 7.6.100 R99 Register (Offset = 0x63) [reset = 0x0]
      101. 7.6.101 R100 Register (Offset = 0x64) [reset = 0x0]
      102. 7.6.102 R101 Register (Offset = 0x65) [reset = 0x0]
      103. 7.6.103 R102 Register (Offset = 0x66) [reset = 0x0]
      104. 7.6.104 R103 Register (Offset = 0x67) [reset = 0x0]
      105. 7.6.105 R104 Register (Offset = 0x68) [reset = 0x0]
      106. 7.6.106 R105 Register (Offset = 0x69) [reset = 0x440]
      107. 7.6.107 R106 Register (Offset = 0x6A) [reset = 0x7]
      108. 7.6.108 R107 Register (Offset = 0x6B) [reset = 0x0]
      109. 7.6.109 R108 Register (Offset = 0x6C) [reset = 0x0]
      110. 7.6.110 R109 Register (Offset = 0x6D) [reset = 0x0]
      111. 7.6.111 R110 Register (Offset = 0x6E) [reset = 0x0]
      112. 7.6.112 R111 Register (Offset = 0x6F) [reset = 0x0]
      113. 7.6.113 R112 Register (Offset = 0x70) [reset = 0x0]
      114. 7.6.114 R113 Register (Offset = 0x71) [reset = 0x0]
      115. 7.6.115 R114 Register (Offset = 0x72) [reset = 0x0]
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 OSCIN Configuration
      2. 8.1.2 OSCIN Slew Rate
      3. 8.1.3 RF Output Buffer Power Control
      4. 8.1.4 RF Output Buffer Pullup
        1. 8.1.4.1 Resistor Pullup
        2. 8.1.4.2 Inductor Pullup
        3. 8.1.4.3 Combination Pullup
      5. 8.1.5 RF Output Treatment for the Complimentary Side
        1. 8.1.5.1 Single-Ended Termination of Unused Output
        2. 8.1.5.2 Differential Termination
      6. 8.1.6 External Loop Filter
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RTC|48
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.1 Overview

The LMX2694-SEP is a high-performance, wideband frequency synthesizer with an integrated VCO and output divider. The VCO operates from 7550 to 15100 MHz, and can be combined with the output divider to produce any frequency in the range of 39.3 MHz to 15.1 GHz. There are two dividers within the input path.

The PLL is fractional-N PLL with a programmable delta-sigma modulator up to the 3rd order. The fractional denominator is a programmable 32-bit long that can provide fine frequency steps easily below 1-Hz resolution, as well as be used to do exact fractions like 1/3, 7/1000, and so on.

For applications where deterministic or adjustable phase is desired, the SYNC pin can be used to get the phase relationship between the OSCIN and RFOUTx pins deterministic. Once this is done, the phase can be adjusted in very fine steps of the VCO period divided by the fractional denominator.

The ultra-fast VCO calibration is designed for applications where the frequency must be swept or abruptly changed. The frequency can be manually programmed.

For JESD204B support, the RFOUTB output can be used as a differential SYSREF output that can be either a single pulse or a series of pulses that occur at a programmable distance away from the rising edges of the output signal.

The LMX2694-SEP device requires only a single 3.3-V power supply. The internal power supplies are provided by integrated LDOs, eliminating the need for high-performance external LDOs.

Table 7-1 shows the range of several of the doubler, dividers, and fractional settings.

Table 7-1 Range of Doubler, Divider, and Fractional Settings
PARAMETERMINMAXCOMMENTS
OSCIN doubler0 (1X)1 (2X)The low noise doubler can be used to increase the phase detector frequency to improve phase noise and avoid spurs. This is in reference to the OSC_2X bit.
Pre-R divider1 (bypass)128Only use the Pre-R divider if the input frequency is too high for the Post-R divider.
Post-R divider1 (bypass)255The maximum input frequency for the Post-R divider is 250 MHz. Use the Pre-R divider if necessary.
N divider≥ 28524287The minimum divide depends on modulator order and VCO frequency. See Section 7.3.5 for more details.
Fractional numerator / denominator1 (integer mode)232 – 1 = 4294967295The fractional denominator is programmable and can assume any value between 1 and 232– 1. It is not a fixed denominator.
Fractional order03Order 0 is integer mode, and the order can be programmed.
Channel divider1 (bypass)192This is the series of several dividers. Also, be aware that above 10 GHz, the maximum allowable channel divider value is 6.
Output frequency39.3 MHz15.1 GHzThis is implied by the minimum VCO frequency divided by the maximum channel divider value.