Hi!

I have a chip on a board (Linear Technology part
number LTC3414) found here:
http://www.linear.com/pdf/3414f.pdf

It has a pad (pin number 21) that is underneath and a
note that says: "To maximize the thermal performance
of the LTC3414, the exposed pad should be soldered to
a ground plane."

I built the footprint and made sure the pad was
soldermasked and included the pad shape in the
pastemask file.

The engineer was trouble-shooting and de-soldered the
part from the board.  It looks like there was no
solderpaste or solder on the pad.

Here's the (dumb) designer question:  How would the
solder get to that pad underneath? Should we add a
requirement note saying that the part should be
inspected or x-rayed to see if the pad is indeed
soldered?

Thanks for all and any suggestions.

Regards,

Bob Wilson
www.cstone-design.com
[log in to unmask]

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