Re: gEDA-user: size of 0402 footprint

[Steve Meier <smeier@xxxxxxxxxxxxxxxxxxx>]

I guess I could have included the land patter so now I will


On Mon, 2008-07-14 at 12:16 -0700, Steve Meier wrote:
> The IPC SM-782A specification for the 0402
> 
> in mm
> 
> Package
> 
> Length min 1.00 
> Length max 1.10 
> pad separation min 0.40 
> pad separation max 0.70 
> Width min 0.48 
> width max 0.60 
> pad length min 0.10 
> pad length max 0.30 
> height max 0.40
> 
> Length = Pad Length + pad separation + Pad Length
> 
> 
> 
> 
> 
> 
> Land Pattern 
> 
> length is along the x axis
> width is along the y axis
> both pads are on the x axis
> 
> Center of pad to center of pad = 1.30
> pad length = 0.9
> pad width = 0.7
> 
> 
> 
> 
> Note: IPC land pattern specs tend to be pessimistic (larger) then most
> component manufacturers recommend.
> 
> using the IPC suggestions you end up with a Land Pattern of 2.2mm by 0.7
> mm for a device which is 1 mm by 0.5 mm
> 
> 
> 
> 
> 
> Steve Meier
> 
> 
> On Mon, 2008-07-14 at 10:49 -0400, Dan McMahill wrote:
> > Kai-Martin Knaak wrote:
> > > On Mon, 14 Jul 2008 00:55:33 -0400, DJ Delorie wrote:
> > > 
> > >> What's the difference between the RES, CAP, and IND variants?
> > > 
> > > http://lilalaser.de/tmp/1005_footprints_in_geda_lib.png
> > > 
> > > The gap seems to be smallest for inductors and largest for resistors. Pad 
> > > size is different too.
> > 
> > small differences in nominal dimensions of the packages.  One problem is 
> > that evidentially there is no standard that fully defines what a '1005' 
> > (aka 0402 in imperial units) package is.
> > 
> > You might get some amusement (or you may be disgusted) from this:
> > 
> > http://www.pcblibraries.com/Forum/forum_posts.asp?TID=1719
> > 
> > It mentions the lack of standards for SMT resistors but really shows the 
> > problem with SOT-23's...
> > 
> > -Dan
> > 
> > 
> > _______________________________________________
> > geda-user mailing list
> > geda-user@xxxxxxxxxxxxxx
> > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
> 
> 
> 
> _______________________________________________
> geda-user mailing list
> geda-user@xxxxxxxxxxxxxx
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#-----------------------------------------------------------------------------------
#  Surface Mount Chip Capacitor 1005 [0402] landpattern
#  IPC Registered Land Pattern Number 130A
#
#  Photoimagable deposition of solder mask
#
#  Author:  Stephen Meier
#
#  email: smeier@xxxxxxxxxx
#
#  Version: 0.01 12/7/2004   Original
#
#  Standards Compliance:
#     IPC-SM-782A     
#     EIA/IS 535BAAE
#     IPC-2221A
#     IPC-SM-840C
#
#  Copyright (c) 2004 MRA Tek LLC
#
# This land pattern is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#
#-----------------------------------------------------------------------------------


Element(0x00000000 "chip cap 1005 [0402] 130A" "C1" "1005 130A" 1410 2275 -70 -100 0 100 0x00000000)
(
	Pad [ -444     0    394    0 2756 2756 3760 "1" "1" 0x00000100]
	Pad [ 4724     0   5562    0 2756 2756 3760 "2" "2" 0x00000100]
	ElementLine ( -32 -18  83  -18  6)
	ElementLine (  83 -18  83   18  6)
	ElementLine (  83  18 -32   18  6)
	ElementLine ( -32  18 -32  -18  6)
)


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