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.6 NCO Frequency and Phase Correction (Strategy #1)

This strategy uses a periodic reference signal to correct any upsets in the NCO accumulator. This strategy is appropriate for phased-array systems or other systems where the NCO phase must remain coherent with other system components, including other DAC39RF10-SP parts.

  1. Program NCO_AR = 1 to configure the accumulator to be reset on every synchronization event.
  2. Configure the NCO to use SYSREF as the synchronization source (NCO_SYNC_SRC = 2). Program SPI_SYNC = 1.
  3. Verify the SYSREF generator is configured for continuous/periodic output.
  4. Since the accumulator will be reset periodically, you must ensure that the programmed NCO frequency is an integer multiple of the SYSREF frequency. Consider the frequency raster that your system requires when you choose the SYSREF frequency.
  5. If you cannot choose a SYSREF frequency that satisfies your frequency raster and is also a sub-harmonic of the multi-frame/EMB frequency, then you can use the LSB of the JESD204C data stream to periodically synchronize the NCO. Use NCO_SYNC_SRC = 3, and provide a periodic reference signal on the LSB of the I samples for DUC0.
  6. If any NCO accumulator or internal frequency register is upset, it will be restored on the next synchronization event.