Our client required us to design a motherboard for their latest Augmented Reality headset

Challenges

  • The use of a mixed pitch, fine pitch, high pin count BGA processor meant that current board fabrication technology would not work with this design.
  • Reduced board area restricted optimal component placement and routing area to meet signal timing constraints
  • High current consumption with limited area to deliver power

Solution

  • Close collaboration with industry leading fabricators in the US and China allowed us to devise a suitable board technology.
  • Simulate none timing compliant nets to ensure design functionality

Outcome and technologies

  • 4-6-4 sequential build :4 layers of microvia per side, core via spanning 6 layers
  • Mixed copper weights for signal and power layers
  • 60um trace, 60um gap
  • Intel Skylake sixth generation core M7 Processor, 1515 pin, 0.4mm staggered pitch FCBGA
  • DDR3, Ethernet, USB3, PCIE
  • 7 different differential and single ended impedances values, 78 separate Relative Propagation Delay groups (tolerance down to 6ps)