Visible to Intel only — GUID: joc1463335708172
Ixiasoft
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
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)
Visible to Intel only — GUID: joc1463335708172
Ixiasoft
Sweeping Anti-pad Radius
Figure 41. Differential Return Loss and TDR Impedance Performances for 0402 AC Capacitors by Various Anti-pad SizesFigure shows a fixed rectangular GND cutout under the capacitors while changing only the signal via anti-pad radius.
![](/content/dam/docs/us/en/683132/current/joc1463335821748.png)
The large via anti-pad increases the impedance of the structure. Using a 22 mil via anti-pad is an optimum solution for the 0402 capacitor and results in the least mismatching with the rest of the system.