Subject: Re: EDA Software
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Date: Wed, 25 Sep 2002 07:23:04 GMT
NNTP-Posting-Date: Wed, 25 Sep 2002 09:23:04 MET DST
"Geraldo Sazias" schrieb im Newsbeitrag
> "Trampas" wrote in message
> > Hi,
> > I am new to this group and was getting ready to start a project where I
> > be designing a PCB as such I was wondering if anyone had any suggestions
> > PCB and schematic capture programs?
> > Basically I will be doing surface mount boards with around 4-6 layers. I
> > will be doing about 3-5 projects per year as such I was figuring I would
> > with a good system that is easy to learn, even if I have to pay a little
> > more.
> > I figure that the price range I will be looking for is the $1k to $10k
> > range.
> > Some of the things I will be doing include:
> > BGA parts
> > Multilayer boards
> > FPGAs and CLPDs
> > Some of the questions I have are:
> > Schematic caputre, how easy to use, add parts, etc.
> > Library editing, how easy is it to understand and add parts and
> > layouts.
> > PCB design, how good is the auto router, is their such a thing as a
> > autorouter.
> Try Eagle (http://www.cadsoft.de/).
> There are good autorouters, but the placing of the components is critical
> and you have to do that by hand. In general, you should group the
> as in the schematic, then optimize the placement (keep pressing the
> 'Ratsnest' button).
Eagle is a good advice, I have done all of the above, but the critical parts
1. Use a grid that is not smaller than 1/4 the BGA pitch, place the BGA
exactly on the grid. Fan out the lines. Change the grid settings to 12.5 or
25mil when doing the normal SMD and change the grid whenever another pitch
is used. Do small segments to let all lines finish on the routing grid.
2. try to find a good placement by hand on a sheet of paper first, or start
with the BGA and other multiple pin parts first. place the parts so there
are as few crossings as possible.
3. Now do the clock lines and other critical lines by hand and place the
decoupling caps near the supply pins. Then do the power connections.
4. save the layout and rename it, then try the autorouter with a grid
setting around 1/2 of the smallest design rule (trace or space width).
5. To make a good library part is not as easy, but with the handbook which
only comes with the paid versions of Eagle this is not so difficult.
There are a lot of more tricks to learn, try with a small board first and
then slowly move to more complex designs, have your schematic and board
layout inspected by an experienced engineer (BTW: I do this type of
electronic hardware designer