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

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ID 813671
Date 4/01/2024
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Document Table of Contents
Document Table of Contents x
1. Agilex™ 5 Clocking and PLL Overview 2. Agilex™ 5 Clocking and PLL Architecture and Features 3. Agilex™ 5 Clocking and PLL Design Considerations 4. Clock Control Intel® FPGA IP Core 5. IOPLL Intel® FPGA IP Core 6. Document Revision History for the Clocking and PLL User Guide: Agilex™ 5 FPGAs and SoCs
1. Agilex™ 5 Clocking and PLL Overview x
1.1. Clock Networks Overview 1.2. PLLs Overview
2. Agilex™ 5 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. Agilex™ 5 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 Core 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. Agilex™ 5 Clocking and PLL Overview
2. Agilex™ 5 Clocking and PLL Architecture and Features
3. Agilex™ 5 Clocking and PLL Design Considerations
4. Clock Control Intel® FPGA IP Core
5. IOPLL Intel® FPGA IP Core
6. Document Revision History for the Clocking and PLL User Guide: Agilex™ 5 FPGAs and SoCs

2.2.6.6. External Feedback Mode

In external feedback (EFB) mode, the output of the M counter (fbout) feeds back to the PLL fbin input (using a trace on the board) and becomes part of the feedback loop. EFB mode is only supported for I/O bank I/O PLL, not supported for fabric-feeding I/O PLL.

One of the dual-purpose external clock outputs becomes the fbin input pin in this mode. The external feedback input pin, fbin is phase-aligned with the clock input pin. Aligning these clocks allows you to remove clock delay and skew between devices.

In EFB mode, you must use the same I/O standard on the input clock, feedback input, and clock outputs.

Figure 17. Example of Phase Relationship Between the PLL Clocks in EFB Mode


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