At 12:54 PM 3/11/2012, you wrote:

>Using integrated magnetics saves a *huge* amount of time and vastly
>improves your chances of design success.
>
>Matt Bennett
>Just outside of Austin, TX
>30.51,-97.91

Interesting. Every Ethernet switch that I've opened up has used
non-integrated magnetics, including the whack of Trendnet 8-port
gigabit switches that I upgraded to a year or so ago**.

I would have guessed that for a notebook, integrated magnetics
would be a no-brainer, and that the Ethernet layout would be
far from the most difficult part of the motherboard layout-
the high speed stuff between memory and processor etc. would
be where the challenge would be.

** They use four pieces of these parts for the eight 10/100/1000
ports, and a single 8-position shielded jack assembly.

http://www.bi-tek.com.tw/style/frame/templates4/product_detail.asp?lang=3D2=
&customer_id=3D828&name_id=3D40208&content_set=3Dcolor_2&rid=3D0&id=3D11926=
0

Wiring between the jacks and transformers, and wiring between the
chips and the transformers is pairs of conductors- probably
controlled impedance differential microstrip- I can see the
ground plane on an internal layer, but the stackup would have to
have a very thin layer of prepreg to get to 100R
differential Z given the dimensions (about 4 thou wide with around
10 thou spacing.

Best regards, =20

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.