PCB Design Guidelines (HSSI, EMIF, MIPI, True Differential, PDN) User Guide: Agilex™ 5 FPGAs and SoCs

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ID 821801
Date 8/29/2025
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 (VPBGA and MBGA) 9. Power Distribution Network Design Guidelines 10. Document Revision History for the PCB Design Guidelines (HSSI, EMIF, MIPI, True Differential, PDN) User Guide: Agilex™ 5 FPGAs and SoCs
1. Overview x
1.1. Agilex™ 5 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 4.4. HSSI Reference PCB Stack-up 4.5. Agilex™ 5 GTS Transceiver 4.6. GTS Transceiver PCIe* 4.0 16 GT/s NRZ Interface Design Guidelines 4.7. GTS Transceiver Ethernet 25G NRZ Interface Design Guidelines
4.5. Agilex™ 5 GTS Transceiver x
4.5.1. HSSI Pin-Field Breakout for VPBGA
4.6. GTS Transceiver PCIe* 4.0 16 GT/s NRZ Interface Design Guidelines x
4.6.1. GTS Transceiver Channel Recommendations 4.6.2. General Guidelines for GTS Transceiver PCIe* Gen 4.0 Interface BGA Breakout Optimization 4.6.3. PCIe* Add-In Card Edge Finger
4.7. GTS Transceiver Ethernet 25G NRZ Interface Design Guidelines x
4.7.1. GTS Transceiver Channel Recommendations 4.7.2. General Guidelines for GTS Transceiver Ethernet Interface 4.7.3. Quad Small Form-factor Pluggable Connector Routing 4.7.4. Small Form-factor Pluggable (SFP) Connector Routing 4.7.5. Other Connectors
4.7.5. Other Connectors x
4.7.5.1. ADM/F Connectors 4.7.5.2. DP and HDMI Connectors 4.7.5.3. FMC+ Connectors
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
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. LPDDR5 Interface Design Guidelines 6.4. LPDDR4 Interface Design Guidelines 6.5. DDR4 Interface Design Guidelines 6.6. LPDDR5, LPDDR4, and DDR4 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. LPDDR5 Interface Design Guidelines x
6.3.1. LPDDR5 Memory Down Topology (Single Rank or Dual-Rank)
6.4. LPDDR4 Interface Design Guidelines x
6.4.1. LPDDR4 Memory Down Topology (Up to 32-bits Interface) 6.4.2. Tables for Comprehensive Routing Guidelines for Each LPDDR4 Signal
6.5. DDR4 Interface Design Guidelines x
6.5.1. Single Rank ×8 Memory Down Topology 6.5.2. Single Rank ×16 Memory Down Topology 6.5.3. VREF_CA/RESET Signal Routing Guidelines for Memory Down Topologies 6.5.4. Skew Matching Guidelines for DDR4 Memory Down Configurations 6.5.5. Power Delivery Recommendation for DDR4 Discrete Configurations
9. Power Distribution Network Design Guidelines x
9.1. Agilex™ 5 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™ 5 Device Family PDN Design Summary
9.1. Agilex™ 5 Power Distribution Network Design Guidelines Overview x
9.1.1. Device Guidelines Status for Agilex™ 5 Devices
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
9.2.1.2. Power Tree x
9.2.1.2.1. Recommended Power Tree for SmartVID Devices with GTS Transceiver 9.2.1.2.2. Recommended Power Tree for Non-SmartVID Devices with GTS Transceiver
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™ 5 Package Power Nets and Subsystems Details
9.2.4. Decoupling Capacitors Recommendation x
9.2.4.1. Agilex™ 5 FPGA Packages Board-Level Decoupling Capacitors Summary 9.2.4.2. Agilex™ 5 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 (VPBGA and MBGA)
9. Power Distribution Network Design Guidelines
10. Document Revision History for the PCB Design Guidelines (HSSI, EMIF, MIPI, True Differential, PDN) User Guide: Agilex™ 5 FPGAs and SoCs

4.6.2. General Guidelines for GTS Transceiver PCIe* Gen 4.0 Interface

  • Intra pair skew: ±1mil

BGA Breakout Optimization

Through hole vias with backdrill are used. As outlined in the General Design Considerations section, note the change of impedance control tolerance, total insertion loss, crosstalk and so forth for microstrip routing especially when implementing long microstrip length. Altera recommends 3D field solver simulation for BGA breakout optimization. Try to make return loss lower than -15 dB at Nyquist frequency (lower than -20 dB is better) and control the impedance changing of cut-out area as small as possible (better within ±5 Ω).

Simulation results for 18 mil pad size have been also presented. Both pad sizes can get good performance.

Figure 24. 85 Ω Top Layer Breakout StructureThis figure shows the detailed structures on SoM for the top layer.
Figure 25. 85 Ω Layer 3 Breakout StructureThis figure shows the detailed structures on SoM for the Layer 3 Fan Out.
Figure 26. Simulation Results of Return LossThis figure shows the simulation results of return loss for top layer breakout (left) and Layer 3 breakout (right) using 8 mil drill hole size and 16 mil pad size.
Figure 27. Simulation Results of TDRThis figure shows the simulation results of TDR for top layer breakout (left) and Layer 3 breakout (right) using 8 mil drill hole size and 16 mil pad size.

The impedance is lower due to the large capacitance caused by larger pad size of 18 mil. While the return loss is 3 to 4 dB higher, it meets the -15 dB requirement. A larger anti-pad size such as 30 mil improves return loss performance as shown in the Simulation Results of L3 Breakout Using 18 mil Pad Size figure.

Figure 28. Simulation Results of Layer 3 Breakout Using 18 mil Pad SizeThis figure shows the simulation results using the same cut-out size (left) and larger anti-pad with 30 mil diameter (right).
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