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APRIL 2018 I DESIGN007 MAGAZINE 45 The thickness of this graphene film heat sink ranges from 25–210 um, which is very thin as compared to conventional heat sink towers. The film can contain a layer of anywhere from a few um to tens of um of graphene along with a layer of tens of um of aluminum or copper, or it can simply contain a layer of graphene. This thin and lightweight heat sink film is very suit- able for thermal dissipation for smartphones, iPads, tablets, and other small portable devices as well as small components such as ICs, LEDs, and DDR memory. The graphene film is normally attached to the surface of the heat source, and/or to the top and/or bottom of the PCB. One can apply the film on the inside of the entire front or back of the enclosure covers of various types of phones, or above and/or below the heat source. The film won't interfere with the antenna performance, so it can be applied to the antenna area too, if necessary. Of course, the real application arrangement will depend upon the layout of the device and the location of the heat sources. Focusing further on PCBs, since the heat of the chip radiates through its pins and die top area, it is a good idea to use copper traces, ground planes, and thermal via to speed up the heat transfer and radiation through the gra- phene film. The larger the film area, the better, Figure 3: Add graphene film to the existing aluminum heat sink to improve the heat dissipation, or just use graphene film instead of the aluminum heat sink. Figure 4: Adding graphene film on one side or on both sides of the PCB will reduce the size of the aluminum heat sink.