All decoupling capacitors (0.1 μF and 0.01 μF) must be 0402 or of a smaller package size, as they must be mounted on the back side of the board. They must fit between the adjacent vias of ball grid array (BGA) package pins. These decoupling capacitors are selected to have a low impedance over operating frequency and temperature range. Capacitor pad to via trace must be as small as possible. The following figure shows how these capacitors need to be mounted. Keep the capacitor pad directly on the corresponding vias. The capacitors must not share ground vias. Each decoupling capacitor must have its own via connection to the PCB ground plane.