Clocking and PLL User Guide: Agilex™ 5 FPGAs and SoCs

ID 813671
Date 7/25/2024
Public
Document Table of Contents

3.2. Guidelines: Timing Closure

For timing closure, refer to the following guidelines:

  • Reconfiguring a PLL's counter and loop filter settings changes both the output frequency and the clock uncertainty of that I/O PLL. Dynamic phase shift only affects the output clock phase.
  • The Quartus® Prime Timing Analyzer performs timing analysis for the initial PLL settings only. You must verify that your design closes timing after dynamic reconfiguration or dynamic phase shift.
  • Altera recommends compiling the I/O PLL designs with each intended configuration setting to determine the variation in the clock with the I/O PLL settings by referring to report Compilation Report in Quartus® Prime software.