2 Methods of Heat Dissipation

To address optimizing R_θJA through the bottom side of the device, the most common methods involve efficiently managing heat flow evenly throughout the PCB. Maximizing areas of conduction throughout the PCB is key to maximizing heat dissipation. This includes maximizing trace thickness, layer thickness, and board size.

V_OUT, GND, SW, and V_IN are all nodes from a buck converter that are recommended to have thicker traces and wider copper pours. Increasing the number of layers, and maximizing the thickness of the layers, within the PCB is another way to maximize copper area. A 6-layer board, for example, has much more copper area to dissipate heat than a 4-layer board. The same can be seen with the usage of thicker board layers.

Fully utilizing the advantage of multiple layers requires using the correct thermal vias as well. As show in Figure 2-1, blind vias, which connect an outer layer to the inner layers, limit the heat dissipation to just one side of the board. A buried via, which connects inner layers, limits heat dissipation to just the inner layers of the board. A through hole via goes through all PCB layers, allowing heat to dissipate from the top side, through the inner layers, and out the bottom of the board.

Maximizing conduction surface area allows greater contact with ambient air, which leads to better heat dissipation.