[SI-LIST] Re: Standard for thermal relief on thru hole pins

Gary Thompson wrote:
> 
> Sorry for the slightly off-topic post...
> 
> Anyone know if there is an IPC standard governing the composition of
> thermal reliefs on plane layers for thru-hole components? 

        The rigid board design spec (IPC-2222) has most of a
        page on "how to".  IMHO anyone doing physical design of
        genuine product is really in need of this spec, or its
        variants (for flex, PCMCIA, MCM, etc).

        The gist of the standard comes down to total web widths
        don't exceed 60% of ideal land dia per layer, and is again
        limited to a total of 4mm at 1oz Cu (maintain this ratio
        for other copper weights).  If you need to violate this
        to meet current carrying needs it must be noted, they say
        to do so on the fab drawing but I personally belive it is
        more pertinent on the assembly drawing.

        HTH,
-- 
 
      Jeff Seeger                         Applied CAD Knowledge Inc
      Chief Technical Officer                  Tyngsboro, MA  01879
      jseeger "at" appliedcad "dot" com                978 649 9800
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