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
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

PCB AC Capacitor Placement Layout Recommendation

Figure 47. Recommended 0402 AC Capacitor LayoutFor this layout, there is no dependency on the stackup.

Follow these guidelines for 0402 AC capacitor layout:

  • AC capacitors are mounted on either the top or bottom layers for RX lanes (for some specific interfaces)
  • If the AC capacitor is mounted on the top layer, RX routing must be stripline with back-drill as close to the top layer as possible to reduce the AC capacitor signal via height
  • If the AC capacitor is mounted on the bottom layer, RX routing must be stripline as close as possible to the bottom layer with a back-drill of the via from the top
  • A x B GND cutout under the AC capacitor (only one layer GND cutout)
  • Signal-to-signal via pitch P = 40 mil
  • Signal-to-GND via pitch C = 30 mil
  • Signal/GND via drill diameter = 10 mil
  • Signal/GND via pad diameter = 20 mil
  • Signal anti-pad diameter = 45 mil
Figure 48. Recommended 0201 AC Capacitor LayoutFor this layout, there is no dependency on the stackup.

Follow these guidelines for 0201 AC capacitor layout:

  • A x B GND cutout under the AC capacitor (only one layer GND cutout)
  • Signal-to-signal via pitch P = 40 mil
  • Signal-to-GND via pitch C = 30 mil
  • Signal/GND via drill diameter = 10 mil
  • Signal/GND via pad diameter = 20 mil
  • Signal anti-pad diameter = 45 mil

Where possible, Intel recommends using the 0201 AC capacitor rather than the 0402 AC capacitor for improved differential return loss and TDR performance.

Figure 49. Differential Return Loss and TDR Comparison Between the 0402 and 0201 AC Capacitor LayoutsFigure shows results after optimization of the GND cutout and signal via anti-pad. Both structures use a 22 mil signal via anti-pad radius. The 0201 AC capacitor has a 55 mil GND cutout width and the 0402 AC capacitor has a 90-mil GND cutout width on the first GND layer under the capacitors.
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