# # Tags: # # F Footprint name (must be first) # N Data sheet identifier (N tag of BOOKSHELF; can be omitted if equal to F) # # Standard rectangular passive components F: stdpass # Solder pads and test points F: pads # Printed 8:10 card contacs F: 8_10-card # Fiducial (1 mm copper pad, 2 mm solder mask clearance) F: fiducial # "Generic" simple QFN F: qfn # # The information for these packages comes from various sources: # # - the C8051F326 data sheet, for the QFN28 footprint (N: mcu) # - the AT86F326 data sheet, for the QFN32 package dimensions (N: txrx) # - Atmel's general recommendations for QFN land patterns (N: atmel-qfn) # - NXP's SOT617-1 and SOT617-3, for package and land pattern: # http://www.nxp.com/package/SOT617-1.html # http://www.nxp.com/package/SOT617-3.html # # Solder paste: # # Footprint Center pad Closest NXP (with complete land pattern) # QFN28-Atmel 2.4 mm for further study # QFN28-SiLabs 3.3 mm use SiLab's specification # QFN32-VHHD-2 3.7 mm between SOT818-1 and SOT788-1 # QFN32-VHHD-6 3.4 mm SOT818-1 # # From NXP: # # Package Pad Paste zone Islands Isl. size Isl. gap # SiLabs 3.25 3.1 3 x 3 0.9 # SOT818-1 3.4 1.75 2 x 2 0.75 0.25 # SOT788-1 4.0 2.4 3 x 3 0.6 0.3 # # NXP rules (AN10365): # - paste zone = 35% of pad area # - paste coverge = 20% of pad area # # Our parameters: # # Package Pad Paste zone Islands Isl. size Isl. gap Zone Coverage # QFN32-VHHD-2 3.7 2.15 3 x 3 0.55 0.25 34% 20% # QFN32-VHHD-6 3.4 1.95 2 x 2 0.75 0.45 33% 19% # # Known bugs: # # - really ought to merge all the various QFN definitions (we have more # over at gta02-core) into a single QFN file with a big mean table of # everything # N: sot617-3-lp # "Generic" simple QFP (for now, just for Silabs' C8051F320) F: qfp