15 Apr
2004
15 Apr
'04
1:57 a.m.
der Mouse wrote:
I suspect that there are a lot of things I don't know because I've
never done anything of the sort before that everyone in the industry
takes for granted because it's always been done that way.
(you may well find that in the end, there were/are actually good reasons
for why things "have always been done that way" :-)
You didn't ask, but if I was you, I'd do this:
- grab a copy of the free eagle
- fit your first design into the tiny dimensions the free version allows
(and 2 layers).
- capture the schematic and then do the layout by hand. you'll find you
spend about 90% of your time creating library entries for parts and/or
searching the existing libraries for parts which match. This means
you'll end up with a .pdf file for *every* part and you'll know the
footprint of each part very well. (this part is worth a lot of time -
except for shorting power and ground, parts that don't fit on their
pads/holes is the most common screwup imho).
- use the design rule checking in eagle. it's reasonable (my opinion);
don't stop until it's happy.
- spend some time on the web googling for things like "pcb design rules"
and "design for manufacturability". find sites which talk about proper
trace widths, proper multilayer stackups (i.e. where power and ground
layer(s) should be), how vias affect signals, etc... you could spend a
lifetime on via's alone. I personally love the 3d pictures of signal
returns when vias are used for high frequency signals on 8 layer boards
:-)
- go to www.pcbexpress.com; they have instructions on how to get eagle
to spit out gerber files they can use. they can also take the .brd
files wholesale. I find their service very reliable and their customer
support great. (I use other houses also, but I like pcbexpress - they
have been good to me). Their prices are reasonable for quick turn
(my opinion).
- spend some time looking at the gerbers before you send them off.
- plot your files and send them off the pcbexpress. say a short
prayer. wait for the UPS person to show up.
I would start with a simple 2 layer board. Once that works, try a simple
4 layer board. I would do multiple 4 layers before I went to 6 and
8. Plus, you'll need the commercial version to do that.
-brad