PCB -entering new components

[asjad]

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

[Neutone]

The data sheet usually specifies the dimentions. Also many vendors have datasheets showing how to layout pads.

[Steph]

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

[SherpaDoug]

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.

[Steph]

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.