QFP = Quad FlatPack A generic term for rectangular or square surface-mounting packages with leads on all four sides. Most commonly used to describe packages with gull-wing leads. [Also known as a flatpack, but flatpacks may have gull-wing leads on two sides only] QFP lead pitches are fairly standard (typically 0.8mm; 0.65mm; 0.5mm; 0.4mm), but packages may have pin counts from 44 leads up to 400 or more, there is a wide range of profiles, and much variation in dimensions and tolerances. You will need to consult the data sheet for the particular manufacturer’s part, as a brief description like ‘QFP100’ is inadequate to define the exact mechanical size and lead pitch of the package.