[Arm-netbook] PoE options (Was: eoma68 router pcb)

[luke.leighton]

ok i went for the Ag5300 in the end.  the choices are 12W or 30W.  12W
is definitely not enough, ruling out the 9000 series.  but, 8-211at
needs mode-selection (to a micro-processor). there's not enough spare
pins, so.. y'know what? sod it.  15W is good enough for POE input.
meaning that the Ag5300 won't be pushed hard, overspec'd components
means it won't get massively hot.

although i didn't increase the PCB size too much to get this all on i
did need to make the connectors overhang somewhat - that's ok too.  i
pub on some drill-holes as well, might as well, and made them plated
so they're earth-points as well.  one of them's running through the
POE GND heatsink area which is good news, too.

in the end also i went with a TDK magnetics 1-in, 1-out module and put
24 (!!) of them down.  they're very small.  the advantage is: i could
shuffle them around until i found a good combination for placement.

all very odd, but hey it's a good spec board now.  power input voltage
anywhere between 6 and 21V.  POE option which can *output* 12V via the
power connector (i wired them straight up.  maybe i shouldn't do that
- use diodes, eh?).  found that app note which shows how to do gigabit
PoE...

... whew :)