Kevin:

When the IPC Surface Mount Land Patterns Subcommittee developed 
IPC-SM-782A, a problem they discussed was solder joint cracking of 
capacitors in 1210 sizes and larger. The subcommittee was presented with 
data which indicated that decreasing the size of the land for these 
parts solved the problem. 

I'm not sure about the MELF dimensions, but I will investigate it.

Mike Buetow
IPC Technical Staff
2215 Sanders Road
Northbrook, IL 60062-6135
T: 708-509-9700
F: 708-509-9798
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On Fri, 27 Oct 1995, KEVIN BERRY wrote:

>  To All:
> 
>   Recently when building a 1210 footprint for our CAD design software per
> IPC-SM-782 (subsection 8.2), we noticed that the recommended land dimensions
> for 1210 chip capacitors are smaller than the actual width of the component
> and terminal area of part. We also noticed that it is the same for case sizes
> 1812 and 1825 but not for case sizes lower than 1210.
> 
>  Secondly, We are also curious about the melf package SOD-87/MLL41 footprint
> (subsection 8.5). The recommended footprint is huge compared to the actual
> melf component.
> 
>   If anyone can tell me if these recommended footprint dimensions are
> correct/incorrect and why they are as such please respond.
> 
>   thanks,
> 
> Kevin Berry
> Geco-Prakla, Schlumberger
> 10420 Miller Rd.
> Dallas, Tx. 75238
> [log in to unmask]
> 
>