AN 661: Implementing Fractional PLL Reconfiguration with Altera PLL and Altera PLL Reconfig IP Cores

ID 683640
Date 10/14/2019
Public
Document Table of Contents

1.2. Fractional PLL Dynamic Phase Shifting in the Intel® Quartus® Prime Software

The dynamic phase shifting feature allows the output phases of individual fractional PLL outputs to be dynamically adjusted relative to each other and to the reference clock. The smallest incremental step equals to 1/8th of the VCO period. The output clocks are active during this dynamic phase-shift process.

You can use the following methods to perform dynamic phase shifting:

  • Altera PLL Reconfig IP core
  • Dynamic phase-shifting circuitry using the Altera PLL IP core directly
Note: In the Intel® Quartus® Prime software version 11.1 SP2, you can only perform dynamic phase shifting using the Altera PLL Reconfig IP core. However, you can perform dynamic phase shifting directly using the Altera PLL IP core in the Intel® Quartus® Prime software version 12.0 and later.