Thanks, this was indeed helpful. Also the Yahoo Groups via Google search method. --Jim
On Tue, Aug 24, 2010 at 9:16 AM, Robert <birmingham_spi...@gmx.net> wrote: > > > This has been discussed previously. The Yahoo Groups search tool is > pretty hopeless so I used Google to search for the relevant thread for > you, which it found first in mail-archive starting at: > > http://www.mail-archive.com/kicad-users@yahoogroups.com/msg06539.html > > Does that help? > > Regards, > > Robert. > > > On 24/08/2010 13:33, James Moody wrote: > > A number of components I've come across lately (DC motor controller > chips, > > ESD protection devices, for example) have a thermal or ground pad > underneath > > the chip. This requires that a large pad be included in the footprint, > and > > the usual recommendation is that several vias are used in this pad to > > connect it to the ground layer. This is also part of the thermal > management > > scheme. > > > > For example, if you look at page 10 of the datasheet for the Allegro > A4983, > > it describes how to lay out the board. It shows 9 vias in the under-chip > pad > > used to aid in solder flow and heat transfer. > > > > My first thought for how to do this in KiCad was to define a bunch of > vias > > on the board. My second thought was to change the module so that the > large > > pad was actually several small pads butt up against each other, tiled > > together to make one large pad, and have each pad be a through-hole style > > pad with a very narrow drill. > > > > Is there a better approach or feature I've missed? > > Thanks. > > --Jim > > >
