SBASAC8B May   2023  – March 2024 DAC39RF10 , DAC39RFS10

PRODUCTION DATA  

  1.   1
  2. Features
  3. Applications
  4. Description
  5. Device Comparison
  6. Pin Configuration and Functions
  7. 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: Linearity Sweeps
    16. 6.16 Typical Characteristics: Modulated Waveforms
    17. 6.17 Typical Characteristics: Phase and Amplitude Noise
    18. 6.18 Typical Characteristics: Power Dissipation and Supply Currents
  8. 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. 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 Eye Scan Procedure
      4. 8.1.4 Pre/Post Cursor Analysis Procedure
      5. 8.1.5 Understanding Dual Edge Sampling Modes
      6. 8.1.6 Sleep and Disable Modes
    2. 8.2 Typical Application
      1. 8.2.1 S-Band Radar Transmitter
        1. 8.2.1.1 System Schematic
        2. 8.2.1.2 Design Requirements
        3. 8.2.1.3 Detailed Transmitter Design Procedure
        4. 8.2.1.4 Detailed Clocking Subsystem Design Procedure
          1. 8.2.1.4.1 Example 1: SWAP-C Optimized
          2. 8.2.1.4.2 Example 2: Improved Phase Noise LMX2820 with External VCO
          3. 8.2.1.4.3 Example 3: Discrete Analog PLL for Best DAC Performance
          4. 8.2.1.4.4 10 GHz Clock Generation
        5. 8.2.1.5 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. 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

Multi-Device Synchronization and Deterministic Latency

JESD204C subclass 1 outlines a method to achieve deterministic latency across the serial link. If two devices achieve the same deterministic latency then they can be considered synchronized. This latency must be achieved from system startup to startup to be deterministic. There are two key requirements to achieve deterministic latency. The first is proper capture of SYSREF. SYSREF resets the LMFC counter in each device to act as a known timing reference.

The second requirement is to choose a proper elastic buffer release point in the receiver. The converter device is the receiver (RX) in the JESD204C link and the logic device is the transmitter (TX). The elastic buffer is the key block for achieving deterministic latency and does so by absorbing variations in the propagation delays of the serialized data as the data travels from the transmitter to the receiver. A proper release point is one that provides sufficient margin against delay variations. Choosing a proper release point requires knowing the average arrival time of data at the elastic buffer, referenced to an LMFC edge, and the total expected delay variation for all devices. With this information the region of invalid release points within the LMFC period can be defined, which stretches from the minimum to maximum delay for all lanes. Essentially, the designer must make sure that the data for all lanes arrives at all devices after the previous release point occurs and before the next release point occurs. The invalid region can also be found experimentally - see Programming RBD.

Figure 7-54 provides a simplified timing diagram that demonstrates this requirement. In this figure, the data for two transmitters (ADC or logic device) is shown. The second transmitter (TX 2) has a longer routing distance (tPCB) and results in a longer link delay than the first transmitter (TX 1). First, the invalid region of the LMFC period is marked off as determined by the data arrival times for all devices. Then, the release point is set by using the release buffer delay (RBD) parameter to shift the release point an appropriate number of quad-octet steps from the LMFC edge so that the release point occurs within the valid region of the LMFC cycle. In the case of Figure 7-54, the LMFC edge (RBD = 0) is a good choice for the release point because there is sufficient margin on each side of the valid region.

GUID-E829BE99-92BD-4505-A77F-1EE71A61637B-low.gifFigure 7-54 LMFC Valid Region Definition for Elastic Buffer Release Point Selection

The TX and RX LMFC do not necessarily need to be phase aligned, but knowledge of their phase is important for proper elastic buffer release point selection. Also, the elastic buffer release point occurs within every LMFC cycle, but the buffers only release when all lanes have arrived. Therefore, the total link delay can exceed a single LMFC period; see JESD204B multi-device synchronization: Breaking down the requirements for more information.