With innovation in the technology and attenuation of the electronic devices, the heat generation per unit area on a PCB has amplified extensively. When different components like ICs generate more heat, we typically use a heat sink to disperse this heat away from PCB.
Thermal pads and thermal paste are used to balance improved connectivity between the IC and heat sink. They are highly supportive of transferring heat from the component to the sink. The better the implementation of thermal paste will result in better heat dispersion. If there is no thermal paste, the temperature of an element will rise, then maximum. High heat will cause damage to IC as well as its peripheral PCB.
Another term that becomes popular these days in the electronic device world is thermal relief pcb, and this pad is used in the PCB with the copper pour. Thermal relief pads also look like regular thermal pads, although they have copper-made spokes.
Due to the copper thermal conductivity, there is the possibility of heat coming out of the pad to access the pour; a restriction through direct connection of the thermal relief pad is made with copper pours. This restriction for the heat flow makes easier the soldering process with the pad. A manufacturing brand like Absolute PCB has started using thermal relief pads in their PCBs.
Usually, thermal pads are a large piece of metal, whereas thermal paste comes in liquid form, but both are used for the same cause to conduct heat generating from different components.
We have listed some advantages and disadvantages of using a thermal pad and thermal paste technology that will help you understand their importance more in PCB designs.
- Using a thermal pad is a comparatively clean process and not messy.
- Easy to handle and can be cut into pieces according to your size requirements.
- Available in a wide range of materials allowing you to use it for any material customization.
- They cost a little expensive, and cutting them to precise size adds extra time to the manufacturing process.
- The cost of thermal paste is comparatively low as compared to the thermal pad.
- It is more reliable to apply thermal paste when required.
- It is easy to use with an iron rod and always good to fill uneven gaps and surfaces.
- Thermal paste is in liquid form, so time it becomes messy to handle and dry out.
- Mechanical strength is not equal to a thermal pad.
- Thermal paste results better to use in repeated thermal cycling.
Conclusion: Even though the technique of thermal relief pcb is dependent on manufacturing requirements, but designers always follow cautions using it. The thermal relief has always brought more understanding to the designers of not under-utilizing the heat transfer capability of large copper areas.
PCB involves several aspects of thermal management, such as thermal relief pads. Becoming proficient in all aspects as a designer will ensure a more capable and trustworthy PCB design.