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san2004
Joined: 26 Jun 2007
Posts: 18
Helped: 1
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 24 Jun 2008 17:04 IPC STANDARD FOOTPRINTS |
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Dear Frnds,
Is there any IPC Standard document available for footprints specially for smd packages like PQFP, LQFP, DFN etc.How much should be length more than actual pad e.g. 5 mils, 10 mils or 20 mils etc.
Also for 0402 & 0603 components how much should be pad length & width more than the actual component size 0402 -- 1mm x 0.5 mm so what should be pitch & pad size ?
Thanks in advance,
Byee...
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House_Cat
Joined: 21 Feb 2002
Posts: 1357
Helped: 275
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| 24 Jun 2008 23:25 Re: IPC STANDARD FOOTPRINTS |
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The document is "IPC-7351A Generic Requirements for Surface Mount Design and Land Pattern Standard". You have to buy it from www.ipc.org.
The size of the pad depends on where you are using the footprint. IPC-7351A gives the specs for three different footprint sizes - Least, Norminal, and Most. Those footprint sizes are based on the density of the board on which you are using the footprint. "Most" size is used on low density boards, "Nominal on moderate density boards, and "Least" on high density boards.
If you want to look at the recommended footprints, without buying the standard, you can download a free viewer at: http://landpatterns.ipc.org/default.asp
There's more info available at: http://www.ipc.org/ContentPage.aspx?pageid=4.6
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cyberrat
Joined: 19 Jun 2001
Posts: 903
Helped: 31
Location: In the sewers of the U.K.
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| 25 Jun 2008 8:46 IPC STANDARD FOOTPRINTS |
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There is a free viewer available for this at h**tp://www.pcblibraries.com/
As hey are the ones that defined the IPC STD it is the same.
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san2004
Joined: 26 Jun 2007
Posts: 18
Helped: 1
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| 25 Jun 2008 16:45 Re: IPC STANDARD FOOTPRINTS |
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Thanks a lot frnds !!
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House_Cat
Joined: 21 Feb 2002
Posts: 1357
Helped: 275
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| 25 Jun 2008 23:29 Re: IPC STANDARD FOOTPRINTS |
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| cyberrat wrote: |
There is a free viewer available for this at h**tp://www.pcblibraries.com/
As hey are the ones that defined the IPC STD it is the same. |
This is the same viewer available from the IPC footprints site. I just didn't want to give the PCBlibraries bunch a free commercial. They're a manipulative, money grubbing pack of thieves.
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cyberrat
Joined: 19 Jun 2001
Posts: 903
Helped: 31
Location: In the sewers of the U.K.
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| 26 Jun 2008 9:32 IPC STANDARD FOOTPRINTS |
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good point.
I wont do it again
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senilicus
Joined: 26 Feb 2007
Posts: 66
Helped: 7
Location: The Netherlands
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House_Cat
Joined: 21 Feb 2002
Posts: 1357
Helped: 275
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| 27 Jun 2008 3:36 Re: IPC STANDARD FOOTPRINTS |
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That's an outdated copy of the standard. The effective standard is now IPC-7351A, and the method of calculating the footprint pad size has changed completely in the new standard.
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