On Mon, Jul 19, 2010 at 11:56:48AM -0000, ae5ew wrote:
> Ok. I admit I'm ignorant when it comes to this subject. How is an IC
> lead connected to say layer 8 on a 16 layer PCB.
Via a via :-)
I presume you're talking about through hole components, in which case
the via that forms the hole the IC pin goes through. For SMD, a via must
be drilled.
On a commercially made board this via is through plated and makes
contact with the tracks in the inner layer that you have connected to
it. Some brave souls homebrew 4 layer boards, there are various
strategies for making contact to inner layers in absence of through hole
plating (I presume the hole on the top layer is a little larger so that
a wire can be soldered to both the inner layer and outer layer to make
the connection).
For me a multi layer board normally means fine pitch SMD (already
increases the difficulty level in home making a PCB) as well as multi
layers, so I just use a commercial board house since two lots of
difficult tasks goes from being a fun challenge to frustration! (If push
came to shove, I'd consider a 4 layer board where the inner layers were
power and ground planes).