3.1. Thermal dissipation adopt printed circuit board itself.

The PCB base material which are widely and commonly used is epoxy resin glass fiber laminated sheet (FR4) or phenolic resin glass laminated sheet, and rarely used are CEM-1 material.These substrates have excellent electrical properties and processing properties, but their thermal dissipation performance are not good. Finding a way to dissipate heat from high-heating components, it is almost impossible to expect heat to be conducted by the resin of the PCB itself,but properly to dissipate heat from the surface of the component to the surrounding air.

However, as electronic products have entered the era of miniaturization of components, high-density mounting and PCB assembly, therefore it is not enough to rely on the surface of the component  to dissipate heat through a very small surface area. Meanwhile as the extensive use of some high precious active components such as QFP, BGA and other surface mount devices, the heat generated by these components is transmitted to PCB substrate. Therefore, the best way to solve heat dissipation is to improve the heat dissipation capacity of the PCB body itself that is in direct contact with the heating element, through PCB body to transfer or emit heat.

3.2. Add radiator or heat conducting plate to the high heat-generating device.

When a small number of components in the PCB generate a large amount of heat (less than 3),a radiator or heat pipe can be added to the heating device. If the temperature is still high, the option of using the radiator with with fan can enhance heat dissipation. When the amount of heating devices is relatively large, large heat sink(board) can be used to share the heating. Generally, it is a special heat sink customized according to the position and height of the heating device on the PCB board or cut out different component height positions on a large flat heat sink. Snap the heat dissipation cover on the components surface as a whole, and contact each component for heat dissipation. However, the heat dissipation effects is not good due to the poor consistency of the height during the circuit board assembly and welding of the components.Usually add a soft heat conducting phase change material on the component surface to improve the heat dissipation effect.

3.3. For the electronic devices that adopts free convection air cooling, it is best to arrange integrated circuits (or other devices) vertically or horizontally.

3.4. Through using reasonable track design to implement heat dissipation.

The thermal dissipation of resin in substrate is poor, but the copper traces and plated holes are good conductors of heat dissipation. Therefore, increasing the residual rate of copper foil and increasing the thermal holes are the main means of heat dissipation.

To evaluate the heat dissipation capacity of the printed circuit board, it is necessary to calculate the equivalent thermal conductivity (9 eq) of the composite material composed of various materials with different thermal conductivity-the insulating substrate for the PCB.

3.5. The devices on the same board should be properly arranged as much as possible according to their calorific value and degree of heat dissipation.

Devices with low calorific value or poor heat resistance (such as small transistors, small-scale integrated circuits, electrolytic capacitors) should be placed in the cooling airflow. The uppermost stream (at the entrance). Devices with large heat or good heat resistance (such as power transistors, large-scale integrated circuits, etc.) are placed at the most downstream of the cooling airflow.

3.6. In the horizontal direction, high-power devices are placed as close to the edge of PCB as possible to shorten the heat transfer path; In the vertical direction, high-power devices are placed as close as possible to the top of PCB to reduce the impact of these devices on the temperature of other devices when they operate.

3.7. The heat dissipation of PCB in the electronic devices mainly depends on air flow, so in the initial design, it is necessary to study the air flow path and reasonably configure the device or PCB. When air flows, it always tends to flow in places with low resistance, so when configuring devices on a PCB, avoid leaving a large empty area in a certain zone.The configuration of multiple printed circuit boards in the whole machine should also be paid attention to this problem.

3.8. The temperature-sensitive device is best placed in the lowest temperature area (such as the bottom of the device). Never place it directly above the heating device. It is best to stagger multiple devices on the horizontal plane.

3.9. Place the devices with the highest power consumption and the highest heat generation near to the best heat dissipation position, and do not place the devices with higher heat generation on the corners and peripheral of the circuit board, unless a heat sink is arranged close to it. When setting the power resistance, choose a larger device as much as possible, and make it have enough space for heat dissipation when adjusting the layout of the printed board.

3.10. For the base material of RF power amplifier or LED PCB, prior to choose metal substrates.

3.11. Avoid the concentration of hot spots on the circuit bard, distributing the power evenly on the PCB board as much as possible, and keep the PCB surface temperature performance uniform and consistent.

Usually it is difficult to achieve strict uniform distribution during the design process, but it is necessary to avoid the zones where the power density is too high to prevent hot spots from affecting the normal operation of the entire circuit. If possible, it is necessary to analyze the thermal performance of the circuit board. For example, the thermal performance index analysis software module added in some professional PCB design software can help designers optimize the circuit design.