Device including: - a printed circuit card comprising connection pads on both of its opposite sides and traversed by openings (11, 12, 13, 14), - two assemblies, each comprising: • an integrated circuit (4A, 4B) having an electrically active side and an electrically non active side, • a heat sink (5A, 5B) in thermal contact with the electrically non active side of the integrated circuit (4A, 4B), and • a plate (24A, 24B) with holes, placed between the integrated circuit (4A, 4B) and the heat sink (5A, 5B), - fastening means (16, 17, 18, 19) with springs (25A, 25B, 26A, 26B, 27A, 27B, 28A, 28B), inserted in the openings (11, 12, 13, 14) of the printed circuit card and in the holes of each plate (24A, 24B), which extend through the printed circuit card and through each plate (24A, 24B), fastening both of the assemblies respectively on both of the opposite sides of the printed circuit card for establishing an electrical contact between the electrically active side of the integrated circuit (4A, 4B) of each assembly and the side of the printed circuit card on which said assembly is fastened, characterized in that: - the springs (25A, 25B, 26A, 26B, 27A, 27B, 28A, 28B) of the fastening means (16, 17, 18, 19) put weight against the plates (24A, 24B) by applying a pressure force for securing said electrical contact, and - each assembly further comprises a twist clip (34A, 34B) which connects its heat sink (5A, 5B) with its plate (24A, 24B) so as to exert, on this heat sink - plate set (5A-24A, 5B-24B), a pressure force independent of the pressure force produced by the springs. - a printed circuit card comprising connection pads on both of its opposite sides and traversed by openings (11, 12, 13, 14), - two assemblies, each comprising: • an integrated circuit (4A, 4B) having an electrically active side and an electrically non active side, • a heat sink (5A, 5B) in thermal contact with the electrically non active side of the integrated circuit (4A, 4B), and • a plate (24A, 24B) with holes, placed between the integrated circuit (4A, 4B) and the heat sink (5A, 5B), • an integrated circuit (4A, 4B) having an electrically active side and an electrically non active side, • a heat sink (5A, 5B) in thermal contact with the electrically non active side of the integrated circuit (4A, 4B), and • a plate (24A, 24B) with holes, placed between the integrated circuit (4A, 4B) and the heat sink (5A, 5B), - fastening means (16, 17, 18, 19) with springs (25A, 25B, 26A, 26B, 27A, 27B, 28A, 28B), inserted in the openings (11, 12, 13, 14) of the printed circuit card and in the holes of each plate (24A, 24B), which extend through the printed circuit card and through each plate (24A, 24B), fastening both of the assemblies respectively on both of the opposite sides of the printed circuit card for establishing an electrical contact between the electrically active side of the integrated circuit (4A, 4B) of each assembly and the side of the printed circuit card on which said assembly is fastened, - the springs (25A, 25B, 26A, 26B, 27A, 27B, 28A, 28B) of the fastening means (16, 17, 18, 19) put weight against the plates (24A, 24B) by applying a pressure force for securing said electrical contact, and - each assembly further comprises a twist clip (34A, 34B) which connects its heat sink (5A, 5B) with its plate (24A, 24B) so as to exert, on this heat sink - plate set (5A-24A, 5B-24B), a pressure force independent of the pressure force produced by the springs.