CoolGaN™ Bidirectional Switch 40 V G3 in WLCSP, 4 mΩ The IGK048B041S is a 40 V normally-off bidirectional power transistor housed in a small WLCSP 2.1x2.1 package, enabling high power density designs. Thanks to its very low on-state resistance, it is the ideal choice for reliable performance in demanding applications requiring bidirectional blocking capability such as load switch.