Intel Agilex® 7 Device Family High-Speed Serial Interface Signal Integrity Design Guidelines

ID 683864
Date 6/15/2023
Document Table of Contents

1.3.6. Via Drill Size

  • The aspect ratio (AR) is the ratio of a via length or depth to its drill hole diameter. An AR of 15 is a common manufacturing capability provided by most PCB vendors. PCB vendors define the exact AR based on the board thickness specified by their manufacturing capabilities.
  • To meet the target differential via impedance, the optimized anti-pad size is usually larger than the default via anti-pad which may cause a reference issue for breakout routing in the BGA area. Check via impedance with time domain reflectometry (TDR), and use a teardrop or wider trace segment in the breakout area for a smooth impedance transition to the global area.