small outline (package) (SO)
The SO package is a small-outline package for integrated circuits( IC) used in surface mounting on printed circuit boards.
The SO package requires about 30% to 50% less space than an equivalent dual inline package( DIP). It is also much thinner. SO packages generally have the same PIN layout as DIP ICs.
The type designation is determined by the number of pins. For example, an SO-14 has 14 pins.