Jack,
The Cu pours on top/bot with via ties create a pseudo faraday cage to
protect signals inside.  It does not protect components/signals on the
top/bot of the board.  The goal for the switching supply is to reduce
the AC component of the output: use multiple low ESR caps on output,
encase the switching power supply in a Cu pour (GND), and make all high
current paths wide and short (review datasheet for best component
placement).  To reduce processor emissions: run all high speed signals
on adjacent layer to GND plane, add series resistor (or other
termination method) to damp refections in high speed signals, cutback
power plane from GND plane (20H rule) to reduce emissions from board
edge.  For placement make sure that the power supply is next to the
input power connector (so no power return currents flow under the
processor or other high speed signals).

Good Luck, David Plentovich


Jack C. Olson wrote:

> Should I do something between the power supply
> and the microprocessor?
>

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