Hello ,

With reference to those responsed to the 0.8mm BGA question, Leslie has
shared with us that 0.4mm pad can be used.

Taking reference to the table below (by the way, no one has responsed my
early message),  I would assume that it has ball diameter = 0.5mm as
0.8mm pitch BGA can have ball diameters from  0.3mm to 0.5mm.

I have come across Intel 1.0mm Easy BGA  with 0.43 nomimal ball
diameter, recommending 0.3mm pad. For a newcomer, based on the 20%
reduction recommeded in IPC-7095, the pad diameter would be 0.344mm as
the pitch is more than sufficient  to cater it. Why Intel uses 0.3mm and
not 0.344mm?

Anyone want to share a light?

Regards,
Wee Mei


Lum Wee Mei wrote:

> Hello there,
>
> I was working on some analysis work on BGA pad diameters and its
> correlation to other factors when I come across this Table 6 in
> IPC-7095. I cannot explain the differences found which I highlighted
> in bold.  The table specifies :
>
> Nominal ball szie    Reduction    Nominal Land Dia.     Land Variation
> 0.75                            25%                0.55 (27%)
>              0.60 - 0.50
> 0.60                            25%                0.45 (25%)
>             0.50 - 0.40
> 0.50                            20%                0.40 (20%)
>             0.45 - 0.35
> 0.45                            20%                0.35 (22%)
>             0.35 - 0.25
> 0.40                            20%                0.30 (25%)
>             0.35 - 0.20
> 0.30                            20%                0.25 (17%)
>             0.25 - 0.20
>
> Anyone care to shed a light on the difference in the two percentages
> or how the Nominal Land Dia. value come about or agreed upon. Your
> answers will be deeply appreciated.
>
> Regards,
> Wee Mei
>
>
>


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