PCB Design Paper

Calculation of PCB Track Impedance Paper (PDF)
The use of high-speed circuits requires PCB tracks to be
designed with controlled (characteristic, odd-mode, or
differential) impedances.
Wadell[1] is one of the most comprehensive sources of
equations for evaluating these
impedances.
This source includes many configurations including stripline,
surface microstrip, and their coplanar variants.

Current Carrying Capacity of Vias Paper (PDF)
We are frequently asked about the current carrying
capacity of vias.
To our knowledge, there have been no
studies of this particular topic, although we do know of
people who have useful insights into this issue.
What we offer here are some observations and a conceptual
framework for looking at the issue, with some resulting
guidelines that seem reasonable.

PCB Design Tutorial Paper (PDF)
You've designed your circuit, perhaps even bread boarded
a working prototype, and now it's time to turn it into a nice
Printed Circuit Board (PCB) design. For some designers,
the PCB design will be a natural and easy extension of the
design process. But for many others the process of designing
and laying out a PCB can be a very daunting task.