Issue link: https://iconnect007.uberflip.com/i/1181966
NOVEMBER 2019 I SMT007 MAGAZINE 83
• Solder availability (surface tension forces
equilibrium conditions between TH via,
board surface, and component surface)
Board outline:
• 224 mm x 170 mm size, four layers, ImAg
finish
• PTH vias in the thermal pad are fully
connected with all layers
• Three different boards thicknesses:
93 mils (2.36 mm), 110 mils (2.8 mm),
and 130 mils (3.3 mm)
• One type 0.4-mm pitch QFN component
and one type 0.5-mm pitch QFN component
• 2 x 2, 5 x 5, and 8 x 8 matrix of PTH
exposed via in the thermal pad
• Two solder mask designs (with and
without solder mask
doughnut around vias)
Via diameters are chosen
such that
f1