Detailed explanation of PCB circuit board heat dissipation design principles


1. Temperature sensitive components (electrolytic capacitors, etc.) should be kept away from heat sources as much as possible. For heat sources with a temperature higher than 30 degrees, it is generally required that the distance between the sensitive components and the heat source is not less than 2.5 mm under air-cooled conditions; under natural cold conditions, the distance from the heat source is not less than 4 mm.

 

2. For components and integrated circuit chips that may have heat dissipation problems, space should be kept as much as possible to improve the solution, in order to place metal heat sinks and fans.

 

3. For components and integrated circuit chips that can generate high heat, they should be placed at the air outlet or for convection.

 

4. For the large opening in the heat dissipation ventilation design, a large long hole can be used instead of the small round hole or mesh to reduce the ventilation resistance and noise.

5. During the layout process of the PCB circuit board, space should be reserved as much as possible between the components, between the integrated circuit chips or between the components and the chip, in order to facilitate ventilation and heat dissipation.

 

6. For integrated circuit chips with large heat generation, they should be placed on the motherboard as much as possible in order to avoid overheating of the bottom case. If you place them under the motherboard, you need to leave some space between the chip and the bottom case, so you can take full advantage of the gas flow or the space for improvement.

 

7. For higher components in PCB boards, you should consider placing them in the vents, but be careful not to block the air path.

 

8. In order to ensure good tin-through in the printed circuit board, it is required to connect the heat-insulating tape to the pad for the component pad on the large-area copper foil; for the pad that needs to pass the high current of 5A or more, it cannot be used. Thermal pad.

9. In order to avoid the phenomenon of offset or tombstone after component reflow soldering, for the two ends of the package below 0805 or 0805, the pad should ensure the symmetry of heat dissipation, and the width of the connection part of the pad and the printed conductor is generally Should not exceed 0.3mm.

 

10. For components with high heat in printed circuit boards or integrated circuit chips and heat dissipating components, they should be placed close to the edge of the printed circuit board to reduce the thermal resistance.

 

11. Under the rule, the contact pressure between the heat dissipating components such as the fan and the components that need to be dissipated should be as large as possible, and the contact between the two contact surfaces should be confirmed.

 

12, the shape and size of the fan inlet and the design of the tongue and involute must be careful, and the fan should be kept outside the air inlet without any obstruction between 3~5mm.

 

13. For the heat dissipation solution using the heat pipe, the corresponding area of the heat pipe contact should be increased as much as possible to facilitate the heat conduction of the heat generating component and the integrated circuit chip.