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

7.3.4 SerDes Equalizer

All channels of the DAC38RFxx incorporate an adaptive equalizer, which can compensate for channel insertion loss by attenuating the low frequency components with respect to the high frequency components of the signal, thereby reducing inter-symbol interference. Figure 7-9 shows the response of the equalizer, which can be expressed in terms of the amount of low frequency gain and the frequency up to which this gain is applied (that is, the frequency of the ’zero’). Above the zero frequency, the gain increases at 6 dB/octave until it reaches the high frequency gain.

GUID-6FDFFBBC-098F-4638-9D97-FD0926FB5D21-low.gifFigure 7-9 Equalizer Frequency Response

The equalizer can be configured through fields EQ and EQHLD in register SRDS_CFG1 (8.5.86). Table 7-6 and Table 7-7 summarize the options. When enabled, the receiver equalization logic analyzes data patterns and transition times to determine whether the low frequency gain should be increased or decreased. The decision logic is implemented as a voting algorithm with a relatively long analysis interval. The slow time constant that results reduces the probability of incorrect decisions but allows the equalizer to compensate for the relatively stable response of the channel. The lock time for the adaptive equalizer is data dependent, and so it is not possible to specify a generally applicable absolute limit. However, assuming random data, the maximum lock time will be 6x106 divided by the CDR activity level. For field CDR in register SRDS_CFG1 (8.5.86) = 110, the activity level is 1.5 x 106 UI.

When EQ = 0, finer control of gain boost is available using the EQBOOST IEEE1500 tuning chain field, as shown in Table 7-8.

Table 7-6 Receiver Equalization Configuration
EQEFFECT
[1-0]00No equalization. The equalizer provides a flat response at the maximum gain. This setting may be appropriate if jitter at the receiver occurs predominantly as a result of crosstalk rather than frequency dependent loss.
01Fully adaptive equalization. The zero position is determined by the selected operating rate, and the low frequency gain of the equalizer is determined algorithmically by analyzing the data patterns and transition positions in the received data. This setting should be used for most applications.
10Precursor equalization analysis. The data patterns and transition positions in the received data are analyzed to determine whether the transmit link partner is applying more or less precursor equalization than necessary.
11Postcursor equalization analysis. The data patterns and transition positions in the received data are analyzed to determine whether the transmit link partner is applying more or less post-cursor equalization than necessary.
[2]0Default
1Boost. Equalizer gain boosted by 6 dB, with a 20% reduction in bandwidth, and an increase of 5mW power consumption. May improve performance over long links.
Table 7-7 Receiver Equalizer Hold
EQHOLDEFFECT
0Equalizer adaption enabled. The equalizer adaption and analysis algorithm is enabled. This should be the default state.
1Equalizer adaption held. The equalizer is held in its current state. Additionally, the adaption and analysis algorithm is reset.
Table 7-8 Relationship Between Lane Rate and SerDes PLL Output Frequency
EQBOOSTGAIN BOOST (dB)BANDWIDTH CHANGE (%)POWER INCREASE (mW)
00000
012-300
014105
116-205

When EQ is set to 010 or 011, the equalizer is reconfigured to provide analytical data about the amount of pre and post cursor equalization respectively present in the received signal. This can in turn be used to adjust the equalization settings of the transmitting link partner, where a suitable mechanism for communicating this data back to the transmitter exists. Status information is provided by setting field DTEST in register DTEST (8.5.76) to “0111” for EQOVER and “0110” for EQUNDER. The procedure is as follows:

  1. Enable the equalizer by setting fields EQHLD low and EQ to “001” (register SRDS_CFG1 8.5.86). Allow sufficient time for the equalizer to adapt;
  2. Set EQHLD to 1 to lock the equalizer and reset the adaption algorithm. This also causes both EQOVER and EQUNDER to become low;
  3. Wait at least 48 UI, and proportionately longer if the CDR activity is less than 100%, to make sure the 1 on EQHLD is sampled and acted upon;
  4. Set EQ to “010” or “011”, and EQHLD to 0. The equalization characteristics of the received signal are analyzed (the equalizer response will continue to be locked);
  5. Wait at least 150 × 103 UI to allow time for the analysis to occur, proportionately longer if the CDR activity is less than 100%;
  6. Examine EQOVER and EQUNDER for results of analysis
    • If EQOVER is high, it indicates the signal is over equalized;
    • If EQUNDER is high, it indicates the signal is under equalized;
  7. Set EQHLD to 1;
  8. Repeat items 3–7 if required;
  9. Set EQ to “001”, and EQHLD to 0 to exit analysis mode and return to normal adaptive equalization.

Note:

When changing EQ from one non-zero value to another, EQHLD must already be 1. If this is not the case, there is a chance the equalizer could be reset by a transitory input state (that is, if EQ is momentarily 000). EQHLD can be set to 0 at the same time as EQ is changed.

As the equalizer adaption algorithm is designed to equalize the post cursor, EQOVER or EQUNDER will only be set during post cursor analysis if the amount of post cursor equalization required is more or less than the adaptive equalizer can provide.