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asjad
Joined: 09 Mar 2004 Posts: 52 Location: Greater Manchester - UK
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PCB -entering new components |
Posted: Sun Apr 11, 2004 9:57 am |
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CAD package - EDWIN
Dear All,
Does anyone have any experience in creating new components
in a PCB package.
I am familiar on how to enter information into the package.
Do you simply measure the diemensions with a bog standard ruler??
I am using a ruler with millimeters, but standard compoenents can be
2.54mm (0.1")???
Any advice, tips?? _________________ Best Regards |
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Neutone
Joined: 08 Sep 2003 Posts: 839 Location: Houston
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Posted: Sun Apr 11, 2004 10:55 am |
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The data sheet usually specifies the dimentions. Also many vendors have datasheets showing how to layout pads. |
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Steph
Joined: 06 Dec 2003 Posts: 3
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Posted: Sun Apr 11, 2004 4:22 pm |
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Normally, the footprint standard is in millimeter.
But the real footprint standard name is JEDEC.
look at the end of the pattern name like MCP41010SN
soic 8, that is soic-8 narrow body (150mils).
JEDEC equivalent is MS-012.
Look at different name I found for soic 8 (150 mils) body.
JEDEC SO-8 MS-012.
-SO-8
-SOIC-8
-SO-8 NARROW
-SOIC-8 NARROW
-SO-8 (150mils)
and for so-8 (300 mils)
JEDEC SO-8 MS-013
-SO-8
-SOIC-8
-SO-8 WIDE
-SOIC-8 WIDE
SO-8 (300mils)
the jedec MS-012 must be 150 mils body for each company.
Each time you meet the JEDEC name it should be
the standard for all company pattern name.
When you create a footprint that is very important
to add the JEDEC name:
ex: SO-8 (MS-012)
To create a footprint you can use ipc standard:
http://landpatterns.ipc.org/default.asp |
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SherpaDoug
Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA
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Clarification |
Posted: Mon Apr 12, 2004 11:34 am |
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Note that 1 mil = .001 inch. Most package dimensions are based in inches. _________________ The search for better is endless. Instead simply find very good and get the job done. |
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Steph
Joined: 06 Dec 2003 Posts: 3
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Posted: Mon Apr 12, 2004 5:21 pm |
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TAKE CARE, if you do not have a millimeter on
package dimension.
That is not true footprint are base on millimeter.
If you try to make BGA or flat pack in mils,
you would be on trouble. |
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