Homebrew PCBs

"......It seems to me that the vast majority of
signals would not happen to align with the physical pin you needed in order to attach components side by side" - Andrew

No!!!  the opposite is true. I gave the example of a complex circuit i'm now working on, showing a 16 to 4 bottom layer trace reduction by making the top SMDs present themselves as a "micro-hybrid" ie: RCL SMDs physically lumped together for just these 3 pins off my 64 pin IC. This is repeated throughout the entire circuity to varying degrees. The average "bottom layer" trace reductions looks be at least 60%. 

I then force, by physical placement(ie: T,H,L,etc patterns)of the SMDs themselves to an optimized layout for the most compact and shortest routing path possibale.

This gives me great control especially for the demanding UHF transmission paths.

--- In Homebrew_PCBs@yahoogroups.com, Andrew Villeneuve <andrewmv@...> wrote:
>
> How often can this be practical? It seems to me that the vast majority of
> signals would not happen to align with the physical pin you needed in order
> to attach components side by side. You'd need to space them out and put
> small traces.
> 
> I have seen some clever IC configurations along these lines, though - I've
> once seen on a production board, SMT memory ICs literally stacked atop one
> another, all the top pins soldered directly to the bottom pins, with just
> the chip-enable and write-enable signals broken out independently.
> 
> -Andrew
> 
> On Tue, May 25, 2010 at 10:28 AM, Richard
> <richard.liberatoscioli@...>wrote:
> 
> >
> >
> > .........Yes!
> >
> > Any RCL electronically grouped is "physically grouped" into a very tight
> > formation during the "pick and place"
> >
> 
> 
> [Non-text portions of this message have been removed]
>