For best performance, the following are
recommended:
- Solid ground planes between each signal routing
layer
- Two solid power planes for voltages
- Power and ground pins must be connected to these
planes through a via for each
pin.
- All device pin and via connections to these
planes must use a thermal relief with a minimum of
four
spokes.
- Trace lengths for the component power and ground
pins must be minimized to 0.03 inches or
less.
- Vias should be spaced out to avoid forming slots
on the power
planes.
- High-speed
signals must not cross over a slot in the adjacent
power
planes.
- Vias connecting all the digital layers are
recommended for placement around the edge of the
rigid PCB regions 0.03 inches from the board edges
with
0.1-inch
spacing prior to
routing.
- Placing extra vias is not required if there are
sufficient ground vias due to
standard
ground connections of
devices.
- All signal routing and signal vias must be inside
the perimeter ring of ground
vias.