12 Sep
2004
12 Sep
'04
4:02 p.m.
On Sun, Sep 12, 2004 at 11:35:17PM -0400, William Donzelli wrote:
One could always trade-off between a larger, emptier board and fewer layers.
I haven't priced multi-layer boards in a while, but we used to use 6-layer
boards for Qbus and Unibus designs... ground, Vcc, 2 sets of horizontal and
two sets of vertical traces to avoid routing problems, but that was with a
100% thru-hole design. VAXBI boards were crazier with 10 layers (mandated
by DEC) - the additional layers tended towards the diagonals, also to
solve routing issues with dense thru-hole designs.
An SMT transistorized machine would be an interesting project, but hell to
debug I would imagine.
-ethan
--
Ethan Dicks, A-130-S Current South Pole Weather at 13-Sep-2004 03:50 Z
South Pole Station
PSC 468 Box 400 Temp -53.5 F (-47.5 C) Windchill -85.3 F (-65.2 C)
APO AP 96598 Wind 10.8 kts Grid 329 Barometer 671.6 mb (10945. ft)
Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html
With both
sides in play, that seems likely, but a 12"x12" board is going
to be pricy (at least there won't be many through-holes, just vias; those
things add up).
Exactly. I think a six layer board would be needed, but maybe with some
extremely optimized routing, maybe a four layer. Either way, I doubt there
would be a whole bunch of unused real estate left (or money in your
pocket).