A ball grid array (BGA), which is a type of surface mount packaging, is a pattern of small metallic balls used for integrated circuits. Surface mount refers to either mounting or placing components directly onto a printed circuit board.
BGAs come in a range of packages — from fewer than 10 balls (or pins) per pattern to more than 1,700. An electrical engineer will determine the number of pins on a board during the design phase, which will dictate the complexity of the project and number of layers.