Terminology
QFP
QFP, or Quad Flat Package, is a type of popular surface-mount packaging characterized by lead pins extending from all four sides of the package. These leads are typically in a gull-wing (L-shaped) configuration. While the base material for QFP can be ceramic, metal, or plastic, plastic is the most common. QFP is a widely used multi-pin package for large-scale integration (LSI) chips, not only for digital logic LSIs like microprocessors and gate arrays, but also for analog LSIs such as those used in VTR signal processing and audio signal processing.
The pin pitches for QFP are diverse, including 1.0mm, 0.8mm, 0.65mm, 0.5mm, 0.4mm, and 0.3mm. QFPs with a 0.5mm pin pitch are often specifically referred to as Shrink QFP (SQFP) or Very small Quad Flat Package (VQFP). However, there is some confusion in the naming convention, as some manufacturers also refer to QFPs with 0.65mm and 0.4mm pin pitches as SQFP.