PCB Design Guidelines: Agilex™ 3 FPGAs and SoCs

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ID 853726
Date 8/20/2025
Public
Document Table of Contents
Document Table of Contents x
1. Overview 2. BGA Footprint and Land Pattern 3. General PCB Design Considerations 4. VPBGA PCB Routing Guidelines 5. MBGA PCB Routing Guidelines 6. EMIF PCB Routing Guidelines (VPBGA and MBGA) 7. MIPI Interface Layout Design Guidelines (VPBGA and MBGA) 8. True Differential I/O Interface PCB Routing Guidelines 9. Power Distribution Network Design Guidelines 10. Document Revision History for the PCB Design Guidelines: Agilex™ 3 FPGAs and SoCs
1. Overview x
1.1. Agilex™ 3 FPGAs and SoCs Packages
2. BGA Footprint and Land Pattern x
2.1. Metal-Defined Board Pad 2.2. Spoked Pad 2.3. Wide Trace Metal-Defined Pad 2.4. Solder Mask-Defined Pad 2.5. Recommended Land Patterns
3. General PCB Design Considerations x
3.1. Impedance Tolerances 3.2. Reference Planes 3.3. Layer Assignment 3.4. Via Drill Size 3.5. Fiber Weave 3.6. PCB Traces 3.7. PCB Vias 3.8. AC Coupling Capacitors 3.9. Other Considerations
3.6. PCB Traces x
3.6.1. Zig-Zag Routing 3.6.2. Image Rotation
4. VPBGA PCB Routing Guidelines x
4.1. Pin Distribution and Ball Pitches 4.2. Fan-Out and Routing Strategy 4.3. Power Pins
5. MBGA PCB Routing Guidelines x
5.1. Typical Design Rules For Type-IV HDI in a 0.5 mm MBGA 5.2. HSSI Breakout 5.3. EMIF Breakout 5.4. GTS Transceiver PCIe* 3.0 Interface Design Guidelines 5.5. GTS Transceiver Ethernet 10G NRZ Interface Design Guidelines 5.6. DisplayPort Connectors 5.7. HDMI Connectors
5.4. GTS Transceiver PCIe* 3.0 Interface Design Guidelines x
5.4.1. Channel Recommendations 5.4.2. General Guidelines for PCIe* 3.0 Interface 5.4.3. PCIe* Add-In Card Edge Finger
5.5. GTS Transceiver Ethernet 10G NRZ Interface Design Guidelines x
5.5.1. Channel Recommendations 5.5.2. General Guidelines for Ethernet Interface 5.5.3. Quad Small Form-factor Pluggable and Small Form-factor Pluggable Connector Routing
6. EMIF PCB Routing Guidelines (VPBGA and MBGA) x
6.1. General DDR Signal Routing Guideline on PCB 6.2. General Notes for EMIF Routing Guidelines Table 6.3. LPDDR4 Interface Design Guidelines 6.4. LPDDR4 Simulation Strategy
6.1. General DDR Signal Routing Guideline on PCB x
6.1.1. FPGA DDR Break Out Routing 6.1.2. DRAM Break Out in Layout Routing 6.1.3. Ground Plane and Return Path
6.3. LPDDR4 Interface Design Guidelines x
6.3.1. LPDDR4 Memory Down Topology (Up to 32-bits Interface) 6.3.2. Tables for Comprehensive Routing Guidelines for Each LPDDR4 Signal
8. True Differential I/O Interface PCB Routing Guidelines x
8.1. True Differential I/O Specifications
9. Power Distribution Network Design Guidelines x
9.1. Agilex™ 3 Power Distribution Network Design Guidelines Overview 9.2. Power Delivery Overview 9.3. Board Power Delivery Network Recommendations 9.4. Board LC Recommended Filters for Noise Reduction in Combined Power Delivery Rails 9.5. PCB PDN Design Guideline for Unused GTS Transceiver 9.6. PCB Voltage Regulator Recommendation for PCB Power Rails 9.7. Board PDN Simulations 9.8. Agilex™ 3 Device Family PDN Design Summary
9.2. Power Delivery Overview x
9.2.1. Power Architecture 9.2.2. Rail Merger Requirements 9.2.3. Power Rails Specification 9.2.4. Decoupling Capacitors Recommendation
9.2.1. Power Architecture x
9.2.1.1. Power Budget 9.2.1.2. Power Tree
9.2.3. Power Rails Specification x
9.2.3.1. Power Nets 9.2.3.2. Power Rails Tolerance 9.2.3.3. Power Nets and Transient Specifications
9.2.3.1. Power Nets x
9.2.3.1.1. Agilex™ 3 Package Power Nets and Subsystems Details
9.2.4. Decoupling Capacitors Recommendation x
9.2.4.1. Agilex™ 3 FPGA Packages Board-Level Decoupling Capacitors Summary 9.2.4.2. Agilex™ 3 GTS Transceiver Board-Level Decoupling Capacitors Summary
9.3. Board Power Delivery Network Recommendations x
9.3.1. Board Decoupling Capacitors Guide 9.3.2. FPGA Core Fabric VCC Voltage Regulator Selection 9.3.3. Remote Sense Connections 9.3.4. Load Line Requirements 9.3.5. VCC Core Board Current Slew Rate
9.4. Board LC Recommended Filters for Noise Reduction in Combined Power Delivery Rails x
9.4.1. GTS Transceiver Rail Board Connection and LC Filter Recommendation Under Noisy Voltage Regulator
9.5. PCB PDN Design Guideline for Unused GTS Transceiver x
9.5.1. PDN Design Guideline for Unused GTS Transceiver
1. Overview
2. BGA Footprint and Land Pattern
3. General PCB Design Considerations
4. VPBGA PCB Routing Guidelines
5. MBGA PCB Routing Guidelines
6. EMIF PCB Routing Guidelines (VPBGA and MBGA)
7. MIPI Interface Layout Design Guidelines (VPBGA and MBGA)
8. True Differential I/O Interface PCB Routing Guidelines
9. Power Distribution Network Design Guidelines
10. Document Revision History for the PCB Design Guidelines: Agilex™ 3 FPGAs and SoCs

5.2. HSSI Breakout

This section provides two examples of BGA breakout for the MBGA HSSI area. One breakout example is for top layer and the other is for L3. You can follow similar methodology for fan-out in other layers. Altera recommends that you perform a 3D simulation to optimize the anti-pad sizes. The goal is to minimize the return loss, achieving lower than –15 dB at the Nyquist frequency; preferably lower than –20 dB.
Figure 19. Enlarged View of 0.5 mm Pitch MBGA HSSI AreaIn this figure, the VSSGND pins indicate the ground signals.


In the following figure:

  • The Top Layer Breakout example shows the HSSI signals using microstrip lines with a minimum of 3 mil and a maximum of 3.685 mil in the BGA area. This design conforms to the manufacturing requirements in the Typical Type-IV HDI Design Rules for 0.5 mm MBGA (Micro-via and Buried Via) table.
  • The Layer 3 Breakout example uses an oval cut-out structure on Layer 2 and optionally on Layer 4. The example shows the inner layer HSSI signals in horizontal or vertical direction, with examples of vias fan-outs.
Figure 20. Top Layer and Layer 3 Trace Breakout Examples


In the following figure, the Simulation Results of Return Loss graph shows:

  • The RX line as the result of the Top Layer Breakout example—still lower than –15 dB and up to 8.5 GHz, even without a cut-out structure on Layer 2.
  • The TX line as the results of the Layer 3 Breakout example—still lower than –15 dB and up to 8.5 GHz even without a cut-out structure on Layer 4.
Figure 21. Simulation Results


  • If you use microstrip lines to route high-speed signals, consider key factors such as impedance control, crosstalk, and total insertion loss change as outlined in the general design considerations.
  • If you require longer routing traces, you can fan out on the top layer and transit the HSSI signal to an inner layer.
  • If there is an anti-pad on L2 that crosses L3 traces, you may not need a cut-out structure for the top layer breakout because the BGA landing pad size in MBGA designs is smaller.

Run a simulation to optimize the cut-out sizes for the HSSI signals fan-out based on your specific stack-up. For signals fan out on other layers, follow similar method.

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