AN 766: Intel® Stratix® 10 Devices, High Speed Signal Interface Layout Design Guideline

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ID 683132
Date 3/12/2019
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Document Table of Contents x
Intel® Stratix® 10 Devices, High Speed Signal Interface Layout Design Guideline
Intel® Stratix® 10 Devices, High Speed Signal Interface Layout Design Guideline x
Intel® Stratix® 10 Devices and Transceiver Channels PCB Stackup Selection Guideline Recommendations for High Speed Signal PCB Routing FPGA Fan-out Region Design CFP2/CFP4 Connector Board Layout Design Guideline QSFP+/zSFP/QSFP28 Connector Board Layout Design Guideline SMA 2.4-mm Layout Design Guideline Tyco/Amphenol Interlaken Connector Design Guideline Electrical Specifications Document Revision History for AN 766: Intel® Stratix® 10 Devices, High Speed Signal Interface Layout Design Guideline
FPGA Fan-out Region Design x
Signal Break-out Recommendations FPGA Fan-out Region Routing Recommendations AC Coupling Capacitor Layout and Optimization Guidelines
Signal Break-out Recommendations x
Option 1: Via-In-Pad Topology Option 2: Dog-bone with GND Cutout at BGA Pad Topology Option 3: Micro-via Topology GND Cutout Under BGA Pads in Fan-out Configuration Comparison of Dog-bone with GND Cutout Under the BGA and Via-in-Pad Configurations Trace Shape Routing at the BGA Void Area (Tear Drop Configuration)
FPGA Fan-out Region Routing Recommendations x
Comparison of Conventional and Recommended Break-out Routing Topologies
Comparison of Conventional and Recommended Break-out Routing Topologies x
Conventional Jog-out Routings with Skew-matching Right After Break-out The Impact of Via Height and Via Anti-pad Over Insertion Loss
AC Coupling Capacitor Layout and Optimization Guidelines x
0201 AC Capacitor 0402 AC Capacitor PCB AC Capacitor Placement Layout Recommendation
0201 AC Capacitor x
Sweeping Anti-pad Radius Sweeping Void Width only on the First GND Plane Under the Capacitor
0402 AC Capacitor x
Sweeping Anti-pad Radius Sweeping Void Width Only on the First GND Plane under the Capacitor Adding a Trace Reference to the 0201 AC Capacitor Adding a Trace Reference to the 0402 AC Capacitor
PCB AC Capacitor Placement Layout Recommendation x
What to Avoid for AC Capacitor Configuration
CFP2/CFP4 Connector Board Layout Design Guideline x
CFP2 Host Connector, Module Assembly, and Pinout CFP4 Host Connector, Module Assembly, and Pinout Recommended PCB Design Guideline at the CFP2/CFP4 Connector CFP4 Design Example and Optimization Performance
CFP4 Design Example and Optimization Performance x
CFP4 Connector Layout: Signal Via, Trace Routing Impact, and Optimization Two Different Break-out Routings at the CFP4 Connector Area CFP4 Connector Routing Topologies Design Example Full CFP4 Channel Analysis Design Example (Excluding the Connector) CFP2 Connector Area Layout
QSFP+/zSFP/QSFP28 Connector Board Layout Design Guideline x
QSFP+ Module Assembly and Pinout Recommended PCB Design Guideline for QSFP+/zQSFP/QSFP28 Channels Recommended QSFP+ Signal Routing QSFP28 Example Design and Performance Optimization
SMA 2.4-mm Layout Design Guideline x
SMA 2.4 mm Molex® Connector Assembly PCB Design Guidelines for Channels Using the 2.4 mm Connector 2.4 mm Example Design Performance
PCB Design Guidelines for Channels Using the 2.4 mm Connector x
Recommended PCB layout Design for Version-A SMA 2.4 mm Connector Recommended PCB layout Design for Version-B SMA 2.4 mm Connector Performance Comparison between Option1 and Option2 layout Other 2.4 mm Connectors 2.4 mm Channel Specifications
Tyco/Amphenol Interlaken Connector Design Guideline x
Connector Signal and Pin Assignment
Connector Signal and Pin Assignment x
PCB Design Guidelines for Channels with 25 Gbps + Interlaken Interface Connector Recommendations Interlaken Channel Interface Performance Example
Electrical Specifications x
CEI 28 Very Short Reach (VSR) Specifications for CFP2/CFP4/QSFP+/QSFP28/zQSFP/SMA 2.4 mm Interlaken Interface Specification
Intel® Stratix® 10 Devices, High Speed Signal Interface Layout Design Guideline

Recommended QSFP+ Signal Routing

Figure 78. Recommended Signal Break-out Routing at the QSFP+ Connector Different routing colors indicate different routing layers.

You must ensure that you have a proper GND reference plane for signal routing. The differential lanes in yellow can be routed on any signal layer. The differential lanes in orange can only be routed on any signal layer in which the GND reference layers are not GND02/GND04. This is due to crossing the cutout area below the connector.

The orange differential lanes can be routed from the opposite direction (similar to the yellow lanes) provided that there is adequate space for routing. In this case, all signal layers can be used for signal routing.

Observe these guidelines for improved QSFP+ performance at 28 Gbps on the main channel:

  • Length matching for each pair (between P and N lanes) is required. Both P and N lanes must be in phase to recover the data. The skew matching in a pair is 2 ps.
  • Length matching between pairs is not required unless specified by a designer.
  • For optimized FPGA break-out layout design, refer to FPGA Fan-out Region chapter.
  • Always use the minimum routing length from the FPGA to the connector to minimize insertion loss. Refer to PCS Stackup Selection Guideline chapter for stack-up and material selection, and Recommendations for High Speed Signal PCB Routing chapter for HSSI PCB routing.
  • The insertion and return loss of the channel must meet specifications. Refer to Electrical Specifications chapter.
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