>  I checked the source we use for our footprints and on the TSSOP 28
> pin devices with the bottom tab, they suggest a pad the same size as
> the tab and their common solder paste deposition of 0.006 - 0.008

Ah ! The penny drops. That corresponds to the distance between 
the base of the package and the board so as soon as it wets, it'll 
pull the package down just right.

Thanks,

Steve.


======================================================
Steve Baldwin                Electronic Product Design
TLA Microsystems Ltd         Microcontroller Specialists
PO Box 15-680, New Lynn      http://www.tla.co.nz
Auckland, New Zealand        ph  +64 9 820-2221
email: [EMAIL PROTECTED]      fax +64 9 820-1929
======================================================

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