This is the PP3V42_G3H regulator IC for certain model Macbooks. It turns either 18v, 16v, 12v, or 8v into 3.42v. If you want the surrounding resistors & diodes for different board types, look below! Please check to ensure that this is the proper chip for your logic board.
Compatible boards - 820-2915 820-2914 820-3115 820-2936