Abstract: A three phase invertor has five coplanar leadframes for 2d-c terminals and 3a-c terminals. Power MOSFETs soldered around the periphery of one of the d-c leadframes are wire bonded to adjacent ones of the 3a-c leadframes which are mounted alongside the two edges and an end of one of the d-c leadframes. Further switching die are soldered to the 3a-c leadframes and wire bonded to the other d-c leadframe. The die are spaced along and follow a general U-shaped path. The leadframes are mounted on a heat sink which receives an insulation spacer and cap to form a hermetically sealed volume around the leadframes and die. The heat sink has cavities to mount bus capacitors and has a water cooling channel which follows and is below the U-shaped path of the die.