SBAK043 April   2026 DAC39RF10-SP , DAC39RFS10-SP

 

  1.   1
  2.   2
  3.   Trademarks
  4. 1Introduction
  5. 2Single-Event Effects
  6. 3Device and Test Board Information
  7. 4Irradiation Facility and Setup
  8. 5Test Setup and Procedures
  9. 6Single-Event Latch-Up (SEL) Results
  10. 7Single-Event Functional Interrupt (SEFI) Results
    1. 7.1 Converter Performance and Digital (DUC + JESD204C Link) Hardness
    2. 7.2 Configuration Register Hardness
    3. 7.3 SPI Programming During Irradiation
  11. 8SEU Results
    1. 8.1 JESD204C Link Monitoring Results
    2. 8.2 Digital Up-Converter and NCO Upset Recovery
    3. 8.3 Estimating Upset Rates in Unprotected Data Paths
    4. 8.4 Event Rate Calculations
    5. 8.5 Summary of Radiation Hardness
  12. 9References
  13.   A Appendix: Recommendations for Hi-Rel Systems
    1.     A.1 Summary of Rad-Hard Design Features
    2.     A.2 SPI Programming
    3.     A.3 JESD204C Reliability
    4.     A.4 Equalizer Usage in Radiation Environments
    5.     A.5 NCO Reliability
    6.     A.6 NCO Frequency and Phase Correction (Strategy #1)
    7.     A.7 NCO Frequency Correction (Strategy #2)
    8.     A.8 NCO Self-Sync/Self-Coherent Mode (Strategy #3)

A.5 NCO Reliability

The NCO does not include radiation immune flip-flops. However there are several strategies that can be employed to make sure the NCO recovers from upset events. These are summarized in the following table and detailed in the following sections.

Strategy Summary
1 Protect frequency and phase using SYSREF or JESD204C interface
  • Appropriate for phased arrays using more than one DAC39RF10-SP product
  • Maintains phase coherency between multiple DAC39RF10-SP chips or other components
  • NCO frequency must be a harmonic of SYSREF or the JESD204C synchronization bit
2 Protect frequency only using SYSREF
  • Appropriate for systems not requiring phase coherency
  • NCO frequency is not restricted to a harmonic of SYSREF
  • Cannot maintain phase coherence between multiple NCOs (even within one DAC39RF10-SP)
3 NCO self-sync (NCO_SS), and NCO self-coherent mode (NCO_SC)
  • Appropriate for phased array systems utilizing one DAC39RF-100SP, or for generating multi-tone signals with phase coherency (DDS_EN = 1)
  • SYSREF is not required
  • NCO frequency is not restricted to a harmonic of SYSREF
  • Phase coherency is maintained between the four NCOs inside one DAC39RF10-SP
  • No phase coherency is maintained with components outside the DAC39RF10-SP