An electric sub-assembly has an integrated circuit, which contains at least one power semi-conductor component and additional electronic components, the latter being interconnected and linked to connections by the conductors of a lead frame (1, 2, 3). The lead frame (1, 2, 3) has at least one cooling surface (3), which is connected in a thermally conductive manner to a thermal contact (4) of the integrated circuit or circuits. The cooling surface has a greater surface area than the thermal contact surface (4) of the integrated circuit or circuits and is wider than the parts (1) of the lead frame that are used as electric conductors.