I generated a 4x4mm 0.45mm pitch QFN28 according to the Atmega328P datasheet:
However, the pads on the corners (1+28, 21+22, 14+15, 7+8) are too close to each other, less than 0.2mm apart (when datasheet says the pins are 0.4mm apart because of the chamfer).
The solution that comes to mind is to make the pads on the corner shorter, as I did with pads 1 and 28:
Which gives about 0.3mm clearance:
Is this the proper way to do it? If I just leave the pattern as generated I will most likely get DRC errors depending on the process I pick (0.15mm vs 0.2mm).
I know the assistant is just a tool and not set in stone, but I'd just like some informed answers about the proposed solution. (Or alternatives)
Update after answers:
Thanks to DerStrom8 for the App note. Here follows a comparison of IPC generated and Atmel/Microchip recommended patterns:
Left is Atmel/Microchip App note (~0.266mm), Right is IPC wizard from Altium (~1.77mm)