Re: Pad Size for TQFP Package??

pbdelete@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx wrote:

weg22@xxxxxxxxxx wrote:
Hi all,

I'm designing a PCB for a PIC18F8722 which has a TQFP 80 package. This
is the PCB I've designed for an SMT type device and I was wondering
what the standard pad size is for this? From what I've seen on the
web, they look rectangular, but I'm not sure of the dimensions.

Also, does anyone know of free software capable of laying out a PCB
(could be manually and not through schematic capture) while also being
able to generate the gerber files. I know there are a lot of vendors
out there which let you download their software if you pay for them to
manufacture your PCBs...but I already have someone for this.

Try:
gschem http://www.geda.seul.org/
pcb http://pcb.sourceforge.net/

gsch2pcb will convert your gschem schematics into pcb format.
QFP packages etc.. are included. Just specify footprint=QFP80 (or whatever)
in your schematic attributes. And verify correct output in pcb.
'pcb' will make your gerber files. And let you autoroute or manually adjust
layout.

I've tried it and I cannot recommend it. Gschem is quite good, but it
is very cumbersome to work with. PCB is almost completely useless for
what it is meant to do. The problem with pcb is that it doesn't assign
netnames to a trace. This seems trivial, but it causes major problems
when editing the PCB. Also the copper pours are a nightmare. Another
problem with PCB is that it automatically erases the silkscreen when
it is over pads. Last but not least, most of the standard SMT
footprints are wrong.

If you want something decent, get Eagle like someone else already
suggested.

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