Here's a handy document I found when digging around the NXP website:
http://www.nxp.com/acrobat_download/packages/footprint/FOOTPRINT-HTQFP-HLQFP-LQFP-REFLOW.pdf
It gives the layout as recommended by NXP. Note that the thermal pads
in the center of the layout are for the HTQ packages only and are not
needed for micro-controllers.
Quoting rq1...@q7.com:
Make them all the same size.
Wave soldering pads are sometimes done with larger corners. In my
opinion reflow pads should be equal throughout.
(2009.04.11) kenz...@yahoo.com:
I'm doing the IC layout for the LPC2368 and I have a small discrepancy
in land layouts that I would like clarification for. The package
outline shows all 100 pins the same size, while the PC board footprint
drawing shows the lands slightly larger for the 8 corner pins (two
slightly different pad sizes on the drawing). I checked the
psas_eagle_library.lbr to see how the last team laid out the LPC2148
and I see that they left all the pins the same size, which makes sense
as none of the corner pins appear to be power or ground anyway. Would
there be another valid reason to have the corner pads larger? As it's
only 8 pins, I'm moving forward with them all the same size.
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