Almost every human being understands the importance of heat rules. We know the potential danger of exercising in the sun and how the user must take preventive measures to avoid heat strokes. Most of the things on the planet prefer to be in a tight temperature range, and PCB is no different. Print circuit board material (PCB) is formulated to hold a hot amount of heat. What happens when temperatures rise beyond a specific limit? The performance takes nasal dives if we keep the frequency condition higher. For engineers, such cases are commonly related to the management of heat issues due to unavoidable reasons.
As a PCB designer, you don’t experience fatal risks. The heat distribution plus scattering of heat can easily affect the body and design of the PCB circuit, leading to catastrophic events. Keeping the distribution and dissipation factor in mind, the thermal resistance factor needs to be processed. Because excessive heat can cause damage to your board during operation, you must use an excellent thermal design to avoid expensive delays and turnarounds.
PCB thermal resistance
Considering PCB thermal resistance is very important while designing the PCB. After the prototype is finalized and PCB Assembly is done, we can’t do anything, so it is always advisable to plan PCB thermal resistance beforehand.
PCB thermal resistance can be widely defined as the opposite of the thermal conductivity of the board, which alongside pure (≅ 100% Cu) copper through-hole 386 w / m-k. To find a total thermal resistance for your board, you must enter all the board layers and heat parameters related to the type of flowing material. There are common techniques to identify the value of thermal resistance in a PCB. However, this can lead to complicated analysis software with basic resistance knowledge.
The thermal conductivity of the stack up and your PCB copper conductor settings are essential factors that conclude the thermal efficiency of your circuit board. Therefore, you need to bear the concept of three things. Vias, the heat sink, and active cooling are the terms that we will likely call them. For example, copper on the print circuit board has high thermal conductivity. In contrast, FR4 and other substrate materials have far lower conductivity, and the proper layout and component selection can help heat dissipation as a part of the thermal enhancement.
Conductivity is an unavoidable factor. It needs to be regulated and monitored regularly. If we speak of heat dissipation, this becomes one of the prime factors. Cooling the fan motor becomes a vital aspect of heat regulations. Resetting several factors also helps in the safe execution of the PCB design.
With the material of the exemplary circuit board substrate and a choice of components, you can design a thermal management strategy to help control hot transportation on your board. The range of thermal strategies can assist in heat transportation. How is this fine with us? Yes, it is. It nearly cools down all the required parts and normalizes the temperature. Of course, you must inform this design choice by measuring your PCB thermal resistance and reducing thermal resistance as much as possible.
Best methods for eliminating excessive heat from PCB
We can approach the excessive heat factor in two phases. Let’s segregate and analyze them both.
1. PCB build-up methods for controlling heat
Some of the most preferred ways for monitoring the heat:
- Large metal bearings under the heat act as “thermal” bearings.
- Vias was fulfilled solidly to do heat from thermal approaches into land planes.
- Cooling fans and placement of strategic components to place heat components to the fan circulation path.
Make sure your heat can set up with a thermal pad. For instance, several things like a bottle in the wrong place can also transmit heat. Also, note all mounds from solder on the thermal pad because it can prevent intense contact from doing heat.
2. General PCB heat dissipation techniques
- Thermal through arrays
You can change the PCB to the Onboard Heat Sink by combining thermal through an array in the area filled with copper, as shown above. The idea behind doing it is having heat flowing from the component to the copper area and disappears by air from Vias. Usually, thermal through an array is used for modules and power management components with thermal bearings.
When implementing thermal through an array, remember that it needs to have a large diameter to extinguish the heat effectively in a 0.1 mm area. Also, make sure Vias is not a relief bearing, but the padded hole is connected to the copper area on all sides. Finally, increasing the number of thermal vias further helps heat dissipation.
- Use a broader trace.
A copper trail that does high current builds heat. Therefore, it is essential to increase the width of the trace to maximize heat dissipation into the air. Doing it also reduces thermal resistance from the trail and reduces hotspots.
- Use heatsinks and cooling fans
Passive heat dissipation techniques such as thermals through arrays may not be enough if PCB produces more heat than enough to be removed. In such circumstances, you must insert the heatsink and fan in the design.
Heatsinks are installed on components that produce the most heat, usually voltage regulators, CPUs, MCU, and power transistors. Heatsinks are either screwed to the PCB or left open to the air. In a closed design, a cooling fan is installed to replace the hot air in the environment.
- Select ingredients and elements with the technical analysis of coefficient value
The resistance parameters provide an effective and favorable temperature for the design of certain PCB boards. Let’s take FR-4, for instance. It can widely act as a good substance to insulate heat, resulting in comparatively higher resistance in the thermal factor. But with relatively constant contact, the technical part of the PCB is not managed with essential components.
Employing the suggestions while making a PCB will increase the heat scatterings and conversion of your board. PCB can be managed; you can facilitate a smooth assembly and preserve your board integrity. A good PCB layout decision is basically inclusive of the DFM schedule.
Thus, proper heat management is an essential aspect of PCB design and manufacturing. Starting from the basic components of the board to the adjacent modules, the PCB design is very well built with a strategy. For example, the increasing component density in the current electronic circuit can contribute to thermal problems. Also, PCB design defects and ineffective cooling techniques can cause high temperatures that are not acceptable.