SBAS932 March   2024 DAC39RF10-SEP , DAC39RF10-SP , DAC39RFS10-SEP , DAC39RFS10-SP

PRODMIX  

  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 - AC Specifications
    7. 6.7  Electrical Characteristics - Power Consumption
    8. 6.8  Timing Requirements
    9. 6.9  Switching Characteristics
    10. 6.10 SPI and FRI Timing Diagrams
    11. 6.11 Typical Characteristics: Bandwidth and DC Linearity
    12. 6.12 Typical Characteristics: Single Tone Spectra
    13. 6.13 Typical Characteristics: Dual Tone Spectra
    14. 6.14 Typical Characteristics: Noise Spectral Density
    15. 6.15 Typical Characteristics: Power Dissipation and Supply Currents
    16. 6.16 Typical Characteristics: Linearity Sweeps
    17. 6.17 Typical Characteristics: Modulated Waveforms
    18. 6.18 Typical Characteristics: Phase and Amplitude Noise
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 DAC Output Modes
        1. 7.3.1.1 NRZ Mode
        2. 7.3.1.2 RTZ Mode
        3. 7.3.1.3 RF Mode
        4. 7.3.1.4 DES Mode
      2. 7.3.2 DAC Core
        1. 7.3.2.1 DAC Output Structure
        2. 7.3.2.2 Full-Scale Current Adjustment
      3. 7.3.3 DEM and Dither
      4. 7.3.4 Offset Adjustment
      5. 7.3.5 Clocking Subsystem
        1. 7.3.5.1 SYSREF Frequency Requirements
        2. 7.3.5.2 SYSREF Position Detector and Sampling Position Selection (SYSREF Windowing)
      6. 7.3.6 Digital Signal Processing Blocks
        1. 7.3.6.1 Digital Upconverter (DUC)
          1. 7.3.6.1.1 Interpolation Filters
          2. 7.3.6.1.2 Numerically Controlled Oscillator (NCO)
            1. 7.3.6.1.2.1 Phase-Continuous NCO Update Mode
            2. 7.3.6.1.2.2 Phase-coherent NCO Update Mode
            3. 7.3.6.1.2.3 Phase-sync NCO Update Mode
            4. 7.3.6.1.2.4 NCO Synchronization
              1. 7.3.6.1.2.4.1 JESD204C LSB Synchonization
            5. 7.3.6.1.2.5 NCO Mode Programming
          3. 7.3.6.1.3 Mixer Scaling
        2. 7.3.6.2 Channel Bonder
        3. 7.3.6.3 DES Interpolator
      7. 7.3.7 JESD204C Interface
        1. 7.3.7.1  Deviation from JESD204C Standard
        2. 7.3.7.2  Transport Layer
        3. 7.3.7.3  Scrambler and Descrambler
        4. 7.3.7.4  Link Layer
        5. 7.3.7.5  Physical Layer
        6. 7.3.7.6  Serdes PLL Control
        7. 7.3.7.7  Serdes Crossbar
        8. 7.3.7.8  Multi-Device Synchronization and Deterministic Latency
          1. 7.3.7.8.1 Programming RBD
        9. 7.3.7.9  Operation in Subclass 0 Systems
        10. 7.3.7.10 Link Reset
      8. 7.3.8 Alarm Generation
    4. 7.4 Device Functional Modes
      1. 7.4.1 DUC and DDS Modes
      2. 7.4.2 JESD204C Interface Modes
        1. 7.4.2.1 JESD204C Interface Modes
        2. 7.4.2.2 JESD204C Format Diagrams
          1. 7.4.2.2.1 16-bit Formats
          2. 7.4.2.2.2 12-bit Formats
          3. 7.4.2.2.3 8-bit Formats
      3. 7.4.3 NCO Synchronization Latency
      4. 7.4.4 Data Path Latency
    5. 7.5 Programming
      1. 7.5.1 Using the Standard SPI Interface
        1. 7.5.1.1 SCS
        2. 7.5.1.2 SCLK
        3. 7.5.1.3 SDI
        4. 7.5.1.4 SDO
        5. 7.5.1.5 Serial Interface Protocol
        6. 7.5.1.6 Streaming Mode
      2. 7.5.2 Using the Fast Reconfiguration Interface
      3. 7.5.3 SPI Register Map
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Startup Procedure for DUC/Bypass Mode
      2. 8.1.2 Startup Procedure for DDS Mode
      3. 8.1.3 Understanding Dual Edge Sampling Modes
      4. 8.1.4 Eye Scan Procedure
      5. 8.1.5 Pre/Post Cursor Analysis Procedure
      6. 8.1.6 Sleep and Disable Modes
      7. 8.1.7 Radiation Environment Recommendations
        1. 8.1.7.1 SPI Programming
        2. 8.1.7.2 JESD204C Reliability
        3. 8.1.7.3 NCO Reliability
          1. 8.1.7.3.1 NCO Frequency and Phase Correction (Strategy #1)
          2. 8.1.7.3.2 NCO Frequency Correction (Strategy No. 2)
    2. 8.2 Typical Application
      1. 8.2.1 S-Band Radar Transmitter
      2. 8.2.2 Design Requirements
      3. 8.2.3 Detailed Design Procedure
      4. 8.2.4 Detailed Clocking Subsystem Design Procedure
        1. 8.2.4.1 Example 1: SWAP-C Optimized
        2. 8.2.4.2 Example 2: Improved Phase Noise LMX2820 with External VCO
        3. 8.2.4.3 Example 3: Discrete Analog PLL for Best DAC Performance
        4. 8.2.4.4 10GHz Clock Generation
      5. 8.2.5 Application Curves
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Power Up and Down Sequence
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines and 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

Package Options

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

8.2.4.4 10GHz Clock Generation

For higher sample rates several options are available. First, a DRO can be selected that operates directly at the desired frequency and the multiplier chain and or reference frequency can be modified accordingly.

An alternative is to use dividers and mixers to translate the APLL output to a new higher frequency. Figure 8-11 shows an example for a 10GHz clock synthesizer. This uses the same reference multiplier chain and APLL as described above and adds a mixing stage to translate the DAC clock from 8 to 10GHz.

GUID-20231013-SS0I-X9WC-4GDJ-D53KTQPJGDCP-low.svg Figure 8-11 10GHz Clock Synthesizer

The LMX1204 can operate as a buffer, multiplier or divider. In this case the LMX1204 is used to divide the 8GHz APLL output by 4, which is then mixed with the input to translate the clock to 10GHz. A bandpass filter is required after mixing to remove the LO feedthrough and undesirable mixing products. Figure 8-12 shows the input 8GHz scaled to 10GHz and resulting 10GHz after mixing.

As with the reference multiplier chain, special care must be taken selecting the components and operating points for best phase noise. A slight improvement in noise floor was found by power combining two the of the LMX1204 outputs before feeding the IF input of the mixer.

GUID-20231013-SS0I-X8TC-HXTK-SPN1QTQV887P-low.svg Figure 8-12 8GHz and 10GHz Clock Phase Noise