Intel Agilex® 7 Clocking and PLL User Guide: M-Series

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ID 769001
Date 4/10/2023
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Document Table of Contents
Document Table of Contents x
1. Intel Agilex® 7 FPGA M-Series Clocking and PLL Overview 2. M-Series Clocking and PLL Architecture and Features 3. M-Series Clocking and PLL Design Considerations 4. Clock Control Intel® FPGA IP Core 5. IOPLL Intel® FPGA IP Core 6. Document Revision History for the Intel Agilex® 7 Clocking and PLL User Guide: M-Series
1. Intel Agilex® 7 FPGA M-Series Clocking and PLL Overview x
1.1. Clock Networks Overview 1.2. PLLs Overview
2. M-Series Clocking and PLL Architecture and Features x
2.1. Clock Networks Architecture and Features 2.2. PLLs Architecture and Features
2.1. Clock Networks Architecture and Features x
2.1.1. Clock Network Architecture 2.1.2. Clock Resources 2.1.3. Clock Control Features
2.1.1. Clock Network Architecture x
2.1.1.1. Clock Network Hierarchy 2.1.1.2. Clock Sectors 2.1.1.3. Programmable Clock Routing
2.1.3. Clock Control Features x
2.1.3.1. Clock Gating 2.1.3.2. Clock Divider
2.1.3.1. Clock Gating x
2.1.3.1.1. Root Clock Gate 2.1.3.1.2. Sector Clock Gate 2.1.3.1.3. I/O PLL Clock Gate 2.1.3.1.4. LAB Clock Gate
2.2. PLLs Architecture and Features x
2.2.1. PLL Features 2.2.2. PLL Usage 2.2.3. PLL Locations 2.2.4. PLL Architecture 2.2.5. PLL Control Signals 2.2.6. PLL Feedback Modes 2.2.7. Clock Multiplication and Division 2.2.8. Programmable Phase Shift 2.2.9. Programmable Duty Cycle 2.2.10. PLL Cascading 2.2.11. PLL Input Clock Switchover 2.2.12. PLL Reconfiguration and Dynamic Phase Shift 2.2.13. PLL Calibration
2.2.5. PLL Control Signals x
2.2.5.1. Reset 2.2.5.2. Locked
2.2.6. PLL Feedback Modes x
2.2.6.1. Direct Compensation Mode 2.2.6.2. LVDS Compensation Mode 2.2.6.3. Source Synchronous Compensation Mode 2.2.6.4. Normal Compensation Mode 2.2.6.5. Zero-Delay Buffer Mode 2.2.6.6. External Feedback Mode
2.2.11. PLL Input Clock Switchover x
2.2.11.1. Automatic Switchover 2.2.11.2. Automatic Switchover with Manual Override 2.2.11.3. Manual Clock Switchover
2.2.13. PLL Calibration x
2.2.13.1. Power-Up Calibration 2.2.13.2. User Calibration 2.2.13.3. Static Phase Error Calibration
3. M-Series Clocking and PLL Design Considerations x
3.1. Guidelines: Clock Switchover 3.2. Guidelines: Timing Closure 3.3. Guidelines: Resetting the PLL 3.4. Guidelines: Configuration Constraints 3.5. Clocking Constraints 3.6. IP Core Constraints 3.7. Guideline: Achieving 5% Duty Cycle for fOUT_EXT ≥ 300 MHz Using tx_outclk Port from LVDS SERDES Intel® FPGA IP
4. Clock Control Intel® FPGA IP Core x
4.1. Release Information for Clock Control Intel® FPGA IP 4.2. Clock Control IP Core Parameters 4.3. Clock Control IP Core Ports and Signals
5. IOPLL Intel® FPGA IP Core x
5.1. Release Information for IOPLL Intel® FPGA IP 5.2. IOPLL IP Core Parameters 5.3. IOPLL IP Core Ports and Signals
5.2. IOPLL IP Core Parameters x
5.2.1. IOPLL IP Core Parameters - PLL Tab 5.2.2. IOPLL IP Core Parameters - Settings Tab 5.2.3. IOPLL IP Core Parameters - Cascading Tab 5.2.4. IOPLL IP Core Parameters - Advanced Parameters Tab
1. Intel Agilex® 7 FPGA M-Series Clocking and PLL Overview
2. M-Series Clocking and PLL Architecture and Features
3. M-Series Clocking and PLL Design Considerations
4. Clock Control Intel® FPGA IP Core
5. IOPLL Intel® FPGA IP Core
6. Document Revision History for the Intel Agilex® 7 Clocking and PLL User Guide: M-Series

3.1. Guidelines: Clock Switchover

When implementing clock switchover in M-Series I/O PLLs, refer to the following guidelines:

  • Automatic clock switchover requires that the inclk0 and inclk1 frequencies are within 20% of each other. Failing to meet this requirement causes the clkbad0 and clkbad1 signals to not function properly.
  • When using manual clock switchover, the difference between inclk0 and inclk1 can be more than 100% (2×). However, differences in frequency, phase, or both, of the two clock sources may cause the I/O PLL to lose lock. Resetting the I/O PLL ensures that you maintain the correct phase relationships between the input and output clocks.
  • Both inclk0 and inclk1 must be running when the extswitch signal goes low to initiate the manual clock switchover event. Failing to meet this requirement causes the clock switchover to not function properly.
  • After a switchover occurs, there may be a finite resynchronization period for the I/O PLL to lock onto a new clock. The time it takes for the I/O PLL to relock depends on the I/O PLL configuration.
  • If the phase relationship between the input clock to the I/O PLL and the output clock from the I/O PLL is important in your design, assert the reset signal for at least 10 ns after performing a clock switchover. Wait for the locked signal to go high and be stable before re-enabling the output clocks from the I/O PLL.
  • The VCO frequency gradually decreases when the current clock is lost and then increases as the VCO locks on to the backup clock, as shown in the following figure.
Figure 25. VCO Switchover Operating Frequency


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