SLASEA3D December   2016  – December 2023 DAC38RF80 , DAC38RF83 , DAC38RF84 , DAC38RF85 , DAC38RF90 , DAC38RF93

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 - DC Specifications
    6. 6.6  Electrical Characteristics - Digital Specifications
    7. 6.7  Electrical Characteristics - AC Specifications
    8. 6.8  PLL/VCO Electrical Characteristics
    9. 6.9  Timing Requirements
    10. 6.10 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1  SerDes Inputs
      2. 7.3.2  SerDes Rate
      3. 7.3.3  SerDes PLL
      4. 7.3.4  SerDes Equalizer
      5. 7.3.5  JESD204B Descrambler
      6. 7.3.6  JESD204B Frame Assembly
      7. 7.3.7  SYNC Interface
      8. 7.3.8  Single or Dual Link Configuration
      9. 7.3.9  Multi-Device Synchronization
      10. 7.3.10 SYSREF Capture Circuit
      11. 7.3.11 SerDes Test Modes through Serial Programming
      12. 7.3.12 SerDes Test Modes through IEEE 1500 Programming
      13. 7.3.13 Error Counter
      14. 7.3.14 Eye Scan
      15. 7.3.15 JESD204B Pattern Test
      16. 7.3.16 Multiband DUC (multi-DUC)
        1. 7.3.16.1 Multi-DUC input
        2. 7.3.16.2 Interpolation Filters
        3. 7.3.16.3 JESD204B Modes, Interpolation and Clock phase Programming
        4. 7.3.16.4 Digital Quadrature Modulator
        5. 7.3.16.5 Low Power Coarse Resolution Mixing Modes
        6. 7.3.16.6 Inverse Sinc Filter
        7. 7.3.16.7 Summation Block for Dual DUC Modes
      17. 7.3.17 PA Protection Block
      18. 7.3.18 Gain Block
      19. 7.3.19 Output Summation
      20. 7.3.20 Output Delay
      21. 7.3.21 Polarity Inversion
      22. 7.3.22 Temperature Sensor
      23. 7.3.23 Alarm Monitoring
      24. 7.3.24 Differential Clock Inputs
      25. 7.3.25 CMOS Digital Inputs
      26. 7.3.26 DAC Fullscale Output Current
      27. 7.3.27 Current Steering DAC Architecture
      28. 7.3.28 DAC Transfer Function for DAC38RF83, 93, 85
      29. 7.3.29 DAC Transfer Function for DAC38RF80/90/84
    4. 7.4 Device Functional Modes
      1. 7.4.1 Clocking Modes
      2. 7.4.2 PLL Bypass Mode Programming
      3. 7.4.3 Internal PLL/VCO
      4. 7.4.4 CLKOUT
      5. 7.4.5 Serial Peripheral Interface (SPI)
        1. 7.4.5.1 NORMAL (RW)
        2. 7.4.5.2 WRITE_TO_CLEAR (W0C)
        3. 7.4.5.3 Writing to Reserved Bits
    5. 7.5 Register Maps
      1. 7.5.1  Chip Reset and Configuration Register (address = 0x00) [reset = 0x5803]
      2. 7.5.2  IO Configuration Register (address = 0x01) [reset = 0x1800]
      3. 7.5.3  Lane Single Detect Alarm Mask Register (address = 0x02) [reset = 0xFFFF]
      4. 7.5.4  Clock Alarms Mask Register (address = 0x03) [reset = 0xFFFF
      5. 7.5.5  SERDES Loss of Signal Detection Alarms Register (address = 0x04) [reset = 0x0000]
      6. 7.5.6  SYSREF Alignment Circuit Alarms Register (address = 0x05) [reset = variable]
      7. 7.5.7  Temperature Sensor and PLL Loop Voltage Register (address = 0x06) [reset = variable]
      8. 7.5.8  Page Set Register (address = 0x09) [reset = 0x0000]
      9. 7.5.9  SYSREF Align to r1 and r3 Count Register (address = 0x78) [reset = 0x0000]
      10. 7.5.10 SYSREF Phase Count 1 and 2 Register (address = 0x79) [reset = 0x0000]
      11. 7.5.11 SYSREF Phase Count 3 and 4 Register (address = 0x7A) [reset = 0x0000]
      12. 7.5.12 Vendor ID and Chip Version Register (address = 0x7F) [reset = 0x0009]
      13. 7.5.13 Multi-DUC Configuration (PAP, Interpolation) Register (address = 0x0A) [reset = 0x02B0]
      14. 7.5.14 Multi-DUC Configuration (Mixers) Register (address = 0x0C) [reset = 0x2402]
      15. 7.5.15 JESD FIFO Control Register (address = 0x0D)[reset = 0x8000]
      16. 7.5.16 Alarm Mask 1 Register (address = 0x0E) [reset = 0x00FF]
      17. 7.5.17 Alarm Mask 2 Register (address = 0x0F) [reset = 0xFFFF]
      18. 7.5.18 Alarm Mask 3 Register (address = 0x10) [reset = 0xFFFF]
      19. 7.5.19 Alarm Mask 4 Register (address = 0x11) [reset = 0xFFFF]
      20. 7.5.20 JESD Lane Skew Register (address = 0x12) [reset = 0x0000]
      21. 7.5.21 CMIX Configuration Register (address = 0x17) [reset = 0x0000]
      22. 7.5.22 Output Summation and Delay Register (address = 0x19) [reset = 0x0000]
      23. 7.5.23 NCO Phase Path AB Register (address = 0x1C) [reset = 0x0000]
      24. 7.5.24 NCO Phase Path CD Register (address = 0x1D) [reset = 0x0000]
      25. 7.5.25 NCO Frequency Path AB Register (address = 0x1E-0x20) [reset = 0x0000 0000 0000]
      26. 7.5.26 NCO Frequency Path CD Register (address = 0x21-0x23) [reset = 0x0000 0000 0000]
      27. 7.5.27 SYSREF Use for Clock Divider Register (address = 0x24) [reset = 0x0010]
      28. 7.5.28 Serdes Clock Control Register (address = 0x25) [reset = 0x7700]
      29. 7.5.29 Sync Source Control 1 Register (address = 0x27) [reset = 0x1144]
      30. 7.5.30 Sync Source Control 2 Register (address = 0x28) [reset = 0x0000]
      31. 7.5.31 PAP path AB Gain Attenuation Step Register (address = 0x29) [reset = 0x0000]
      32. 7.5.32 PAP path AB Wait Time Register (address = 0x2A) [reset = 0x0000]
      33. 7.5.33 PAP path CD Gain Attenuation Step Register (address = 0x2B) [reset = 0x0000]
      34. 7.5.34 PAP Path CD Wait Time Register (address = 0x2C) [reset = 0x0000]
      35. 7.5.35 PAP path AB Configuration Register (address = 0x2D) [reset = 0x0FFF]
      36. 7.5.36 PAP path CD Configuration Register (address = 0x2E) [reset = 0x0FFF]
      37. 7.5.37 DAC SPI Configuration Register (address = 0x2F) [reset = 0x0000]
      38. 7.5.38 DAC SPI Constant Register (address = 0x30) [reset = 0x0000]
      39. 7.5.39 Gain for path AB Register (address = 0x32) [reset = 0x0400]
      40. 7.5.40 Gain for path CD Register (address = 0x33) [reset = 0x0400]
      41. 7.5.41 JESD Error Counter Register (address = 0x41) [reset = 0x0000]
      42. 7.5.42 JESD ID 1 Register (address = 0x46) [reset = 0x0044]
      43. 7.5.43 JESD ID 2 Register (address = 0x47) [reset = 0x190A]
      44. 7.5.44 JESD ID 3 and Subclass Register (address = 0x48) [reset = 0x31C3]
      45. 7.5.45 JESD Lane Enable Register (address = 0x4A) [reset = 0x0003]
      46. 7.5.46 JESD RBD Buffer and Frame Octets Register (address = 0x4B) [reset = 0x1300]
      47. 7.5.47 JESD K and L Parameters Register (address = 0x4C) [reset = 0x1303]
      48. 7.5.48 JESD M and S Parameters Register (address = 0x4D) [reset = 0x0100]
      49. 7.5.49 JESD N, HD and SCR Parameters Register (address = 0x4E) [reset = 0x0F4F]
      50. 7.5.50 JESD Character Match and Other Register (address = 0x4F) [reset = 0x1CC1]
      51. 7.5.51 JESD Link Configuration Data Register (address = 0x50) [reset = 0x0000]
      52. 7.5.52 JESD Sync Request Register (address = 0x51) [reset = 0x00FF]
      53. 7.5.53 JESD Error Output Register (address = 0x52) [reset = 0x00FF]
      54. 7.5.54 JESD ILA Check 1 Register (address = 0x53) [reset = 0x0100]
      55. 7.5.55 JESD ILA Check 2 Register (address = 0x54) [reset = 0x8E60]
      56. 7.5.56 JESD SYSREF Mode Register (address = 0x5C) [reset = 0x0001]
      57. 7.5.57 JESD Crossbar Configuration 1 Register (address = 0x5F) [reset = 0x0123]
      58. 7.5.58 JESD Crossbar Configuration 2 Register (address = 0x60) [reset = 0x4567]
      59. 7.5.59 JESD Alarms for Lane 0 Register (address = 0x64) [reset = 0x0000]
      60. 7.5.60 JESD Alarms for Lane 1 Register (address = 0x65) [reset = 0x0000]
      61. 7.5.61 JESD Alarms for Lane 2 Register (address = 0x66) [reset = 0x0000]
      62. 7.5.62 JESD Alarms for Lane 3 Register (address = 0x67) [reset = 0x0000]
      63. 7.5.63 JESD Alarms for Lane 4 Register (address = 0x68) [reset = 0x0000]
      64. 7.5.64 JESD Alarms for Lane 5 Register (address = 0x69) [reset = 0x0000]
      65. 7.5.65 JESD Alarms for Lane 6 Register (address = 0x6A [reset = 0x0000]
      66. 7.5.66 JESD Alarms for Lane 7 Register (address = 0x6B) [reset = 0x0000]
      67. 7.5.67 SYSREF and PAP Alarms Register (address = 0x6C) [reset = 0x0000]
      68. 7.5.68 Clock Divider Alarms 1 Register (address = 0x6D) [reset = 0x0000]
      69. 7.5.69 Clock Configuration Register (address = 0x0A) [reset = 0xFC03]
      70. 7.5.70 Sleep Configuration Register (address = 0x0B) [reset = 0x0022]
      71. 7.5.71 Divided Output Clock Configuration Register (address = 0x0C) [reset = 0x2002]
      72. 7.5.72 DAC Fullscale Current Register (address = 0x0D) [reset = 0xF000]
      73. 7.5.73 Internal SYSREF Generator Register (address = 0x10) [reset = 0x0000]
      74. 7.5.74 Counter for Internal SYSREF Generator Register (address = 0x11) [reset = 0x0000]
      75. 7.5.75 SPI SYSREF for Internal SYSREF Generator Register (address = 0x12) [reset = 0x0000]
      76. 7.5.76 Digital Test Signals Register (address = 0x1B) [reset = 0x0000]
      77. 7.5.77 Sleep Pin Control Register (address = 0x23) [reset = 0xFFFF]
      78. 7.5.78 SYSREF Capture Circuit Control Register (address = 0x24) [reset = 0x1000]
      79. 7.5.79 Clock Input and PLL Configuration Register (address = 0x31) [reset = 0x0200]
      80. 7.5.80 PLL Configuration 1 Register (address = 0x32) [reset = 0x0308]
      81. 7.5.81 PLL Configuration 2 Register (address = 0x33) [reset = 0x4018]
      82. 7.5.82 LVDS Output Configuration Register (address = 0x34) [reset = 0x0000]
      83. 7.5.83 Fuse Farm clock divider Register (address = 0x35) [reset = 0x0018]
      84. 7.5.84 Serdes Clock Configuration Register (address = 0x3B) [reset = 0x1802]
      85. 7.5.85 Serdes PLL Configuration Register (address = 0x3C) [reset = 0x8228]
      86. 7.5.86 Serdes Configuration 1 Register (address = 0x3D) [reset = 0x0x0088]
      87. 7.5.87 Serdes Configuration 2 Register (address = 0x3E) [reset = 0x0x0909]
      88. 7.5.88 Serdes Polarity Control Register (address = 0x3F) [reset = 0x0000]
      89. 7.5.89 JESD204B SYNCB OUTPUT Register (address = 0x76) [reset = 0x0000]
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Start-up Sequence
    2. 8.2 Typical Application: Multi-band Radio Frequency Transmitter
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Calculating the JESD204B SerDes Rate
        2. 8.2.2.2 Calculating valid JESD204B SYSREF Frequency
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Power Supply Sequencing
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.4.3 Internal PLL/VCO

The DAC38RFxx has an internal clock generation circuit consisting of a PLL and two selectable VCOs, as shown in Figure 7-30.

GUID-86FBF7E5-1D36-4E2F-91E6-E987EA276378-low.gifFigure 7-30 Internal PLL/VCO Block Diagram

The low VCO is tuned to a target center frequency of 5.9 GHz, and the high VCO is tuned to a target center frequency of 8.85 GHz. The VCO is selected through field PLL_VCOSEL in register PLL_CONFIG2 (8.5.81), with ‘0’ selecting the low VCO and a ‘1’ the high VCO. The 7 bit VCO tuning code in field PLL_VCO in register PLL_CONFIG2 (8.5.81) is used to tune the VCO frequency in the range of 5.24 GHz to 6.72 GHz for low VCO and 7.96 GHz to 9.0 GHz for the high VCO. For the low VCO the center VCO frequency is achieved with PLL_VCO = 63decimal and for the high VCO the target VCO center frequency is achieved with PLL_VCO = 63decimal.

The supply current, and therefore; the analog signal amplitude in the VCO is controlled using the field PLL_VCO_RDAC in register PLL_CONFIG1 (8.5.80). This control signal should be set 15decimal initially for 18 mA supply current in the VCO and ~1.4 VPP single ended oscillation amplitude.

The PLL has no prescaler, so the DAC sample rate is the VCO frequency. In the PLL feedback path a fixed ÷ 4 frequency divider block receives the VCO output clock and divides its frequency by 4. The maximum operating frequency of the phase-frequency detector (PFD) is approximately 550 MHz. The M (feedback) clock divider takes the output clock signal from the fixed ÷4 block and divides it by a programmable ratio set by the 8-bit field in field PLL_M_M1 in register PLL_CONFIG1 (8.5.80). The programmable division ratio range is ÷1 to ÷256, and is the value of the 8 bit unsigned binary code + 1. Although it is possible to program the M divider to ÷1, ÷2 and ÷3, these values should not be used. As stated previously the PFD and CP have a finite maximum operating frequency, which is the VCO frequency divided by the fixed divider ratio multiplied by the minimum allowable M divider ratio.

Equation 18. GUID-B013E315-FE74-4B14-AC80-0AE6F1372214-low.gif

The N (reference) divider determines the ratio between the input reference clock frequency and the PFD operating frequency, and is set by the 5-bit field PLL_N_M1 in register CLK_PLL_CFG (8.5.79). The division ratio range is ÷1 to ÷32, and is the value of the 5-bit unsigned binary code + 1.

The charge pump output current amplitude is set using the 4-bit field PLL_CP_ADJ in register PLL_CONFIG2 (8.5.81). The current amplitude is simply the digital code multiplied by the unit current amplitude of 100 µA. In a nominal condition, with the LF VCO running at 5.898 GHz, and with the M divider set to ÷4, the PFD will run at 368.625 MHz, and the change pump current should set to 6decimal, which gives 600 µA charge pump output current for a good phase margin of 69 degrees. If a higher M ratio (for lower PFD frequencies) are required the charge pump output current must be increased to maintain good loop stability and prevent excessive peaking in the phase noise response. The charge pump output current setting PLL_CP_ADJ should be adjusted in relation to the feedback (M) divider ratio PLL_M_M1 according to the following table to maintain a constant phase margin of 69 degrees.

Table 7-42 M vs Kp for Maintaining Good Stability
MCP_ADJ
46
69
812
1015

Similarly for the HF VCO running at 8.847 GHz, and with the M divider set to ÷4, the PFD will run at 552.9375 MHz as shown above. Here the change pump current should set to 6decimal, which gives 600 µA charge pump output current for a good phase margin of 69 degrees.