[SI-LIST] Re: Standard for thermal relief on thru hole pins
- From: "Salkow, Steven" <steven.salkow@xxxxxxxx>
- To: "'jseeger@xxxxxxxxxxxxxx'" <jseeger@xxxxxxxxxxxxxx>,si-list@xxxxxxxxxxxxx
- Date: Tue, 20 May 2003 10:44:28 -0700
Another way of stating thermal reliefs is to specify that the conductor area
shall not be decreased by more than n%.
The greater n is the more thermal relief occurs but the ampacity and
inductance go up.
The following table is instructions to the Photoplotter house on how to
detail thermals (th = through holes)
Definitions:
CIRCLE: Round aperture for pads and/or line draws.
SQUARE: Square aperture for pads and/or line draws.
THERMAL: Thermal pads- Inside diameter is shown, airgap to outside
diameter is .015.
4 'X' ties of .020 thickness ea for Thermal call outs up to 75TH.
4 'X' ties of .040 thickness ea for Thermal call outs from 80TH to
149TH.
4 'X' ties of .070 thickness ea for Thermal call outs from 150TH to
199TH.
4 'X' ties of .100 thickness ea for Thermal call outs from 200TH to
300TH.
Steven Salkow
Lockheed Martin
3200 Zanker Rd
San Jose, CA 95134
(408) 473-4058
steven.salkow@xxxxxxxx
Fax (408) 473-3044
> -----Original Message-----
> From: Jeff Seeger [SMTP:jseeger@xxxxxxxxxxxxxx]
> Sent: Tuesday, May 20, 2003 10:15 AM
> To: si-list@xxxxxxxxxxxxx
> Subject: [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
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
> List archives are viewable at:
> //www.freelists.org/archives/si-list
> or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
