We've done similar work using 0603's on what amounts to 0402 pads, with some
modification, and reliability was proven to be better than with traditional
rules.

Earl Moon
----- Original Message -----
From: Grant Emandien <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, September 03, 1999 5:37 AM
Subject: [TN]


> Hi All,
>
> We have received some boards with 1206 caps placed (beautifully I might
> add!) on 0805 pads. Hence only the base of the rectangular-end
terminations
> are soldered i.e. no fillet meniscus on the end terminations. The
> terminations do not appear to overhang the pads and hence the whole bottom
> surface area of the terminations is bedded on the soldered pad (it covers
> about half the pad area). We have done a min/max tolerance exercise on the
> 1206 caps - max tolerance may result in overhang.
>
> Is the integrity of the joint affected?
>
> Any other factors to be considered?
>
> J-STD-001, class 2 gives a maximum and minimum fillet height but not the
> area of the fillet. As per Table 9-5, dimensions A, B, C, D, F, G nor J
> appear to have been compromised.  Or do I view the situation as an
overhang
> problem only, if overhang is compromised? The qty of boards affected is
> small - is it best to rather inspect for overhang?
>
> How do I interpret dimension J in Table 9-5 of J-STD-001?
>
> Thanks
> Grant
>
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