EXC240CB102U added

[Werner Almesberger]

?lvaro Lopes wrote:
> EXC240CB102U added (common-mode choke). B3004 and B3005.

Thanks a lot !

We discussed a few modifications on #gta02-core and in the process
made a few entertaining discoveries in the Openmomo schematics:

- the part number has an extra zero (EXC240CB... vs. EXC24CB...)
  That's why nobody found the data sheet :)

- the circuit symbol is incomplete. It should not only show the
  common mode pair of coils but all four. (The the dot should be
  removed - Panasonic don't have one either.)

- at B4105, the common-mode end and the other end magically
  changed places. Fortunately, they're electrically equivalent.

All this serves as a reminder that we have to review the symbols
not only against Openmoko's schematics but also against the vendor
data sheets.

It's all fixed now. Thanks to Joerg for helping us to make sense
of all this !

- Werner