What is a thermal pad and its application in electronic parts? Read this article for a profound explanation.
We’ll cover a lot on this topic and reveal the benefits of applying this material in electronics.
Also, we’ll look at its main alternative- the thermal paste, and compare and contrast their performances.
So for these and more insights, buckle up and let us get right into it.
What is a Thermal Pad?
A thermal pad on an IC.
It’s part of a conductive material with excellent heat transfer properties.
The role of this material is to relieve the heat from an electronic component where it is highly concentrated to another one that dissipates it away.
Among the commonly used materials for thermal pad manufacturing include graphite and silicon, thanks to their exemplary thermal conductivities.
Electronics manufacturers place them strategically on circuit board components to realize their role.
Often, this is between a material that generates the heat and the one that dissipates it (heat sink).
Often its size varies depending on the prevalent heat in the electronic chip.
Advantages of a Thermal pad
- You don’t need expert skills to apply a thermal pad, and they are also clean to handle, unlike pastes which can stain your hands and clothes.
- Some pads are softer than others, making them easy to mold into the desired shapes. Thus, you can fit them in virtually any component.
- Lastly, they are ideal for hobbyists’ projects and small devices that don’t evolve a lot of heat.
Disadvantages of a Thermal Pad
- Thermal pads can sometimes get permanently attached to the surface of the heat sink or the heat source whose temperature you want to control.
- If you’re on a lean budget, thermal pads may be out of your reach as they are quite pricey.
- Also, these are nonreusable conductive materials you must replace after removing them.
CPU fan heatsinks and CPU grease also regulate heat, but thermal pads are the ultimate heat conduction parts to expel heat off the surface.
But are these the only thermal interface materials?
We have others that include:
- Electrically insulative thermal paste
- Thermal compound
- Liquid metal
- Gap fillers
- Heat spreader
- Thermal gel
- Electrically conductive thermal paste
- Gap pads
- Thermal Metal
Thermal Paste vs. Thermal Pad: Which One Has Improved Heat Transfer
Applying thermal paste.
If you cannot access thermal pads or find their prices larger than your budget, the best option is to go for thermal paste.
But is a thermal paste an ideal like-for-like replacement for a thermal pad?
- Both materials are great thermal interfaces with excellent heat dissipation properties.
- A thermal paste is ideal for CPU surface application primarily because the material fills in the gaps, which is imperative in facilitating heat transfer from the delicate parts. While you can still use a thermal pad for this application, its efficiency will not be as good as that of a paste.
- However, the ideal material for DIY hobbyists without technical application know-how is a thermal pad. Primarily this is because the material is straightforward to apply without hassle.
- The ideal thermal interface material for low-power electronics with flat faces, such as ICs, thermal pads are the best. Conversely, you should use thermal paste when dealing with components with hard-to-reach areas.
What Do Thermal Pads Do?
The primary feature of thermal pads is that they are great in heat dissipation by bridging the gap between the heat sink and the source.
Therefore, they are connectors towards the loss of heat, meaning that there would be heat accumulation on the PCB in their absence.
Another way to look at thermal pads is as filler materials owing to their role in enabling connection in spaces that would otherwise be empty.
Others may also refer to these gap filler pad materials as wet out due to their role as heat transfer fluid.
So how do you rate the quality of a thermal pad? Check out its Watts per meter-Kelvin rating.
A high value of their parameter indicates that it’s an excellent heat conductor.
Also, you can rate this from the hardness of the gap filler pad material.
If it is soft, then it is more efficient in heat transfer than a harder thermal film.
Types of Thermal Pads
Here are the four main types of thermal pads and their respective functions.
|Thermal Pad Type||Thermal Pad Feature|
|Electrically conductive||They lack an electrical current insulation layer, are thin, and allow the conduction of heat and electricity between the components.|
|Non-electrically conductive||These are conductors of heat but don’t allow the passage of electric current. The non-conductive characteristic means that it requires a relatively thicker layer. Nonetheless, this compromises their heat transmission capability. Thus they are less effective than the erstwhile types.|
|Well-matched surfaces Thermal Pads||Their standout feature is that they are best suited to smooth surfaces and are quite thin to fit on these platforms.|
|Poorly matched surfaces Thermal Pads||As their name suggests, they are best suited when dealing with rugged surfaces or heat-generating components that leave large spaces.|
How to Choose a Thermal Pad?
The best thermal pads should have a combination of the following.
- Excellent thermal conductivity
- Low Effective resistance
- Low bond line thickness (BLT)
- Huge compressive modulus
- High clamping pressure.
When Should I Use a Thermal Pad?
There are different parts on which you can use thermal pads, such as the following:
- Control units
- Automotive parts
- Memory chips
- Device solders
- Heating pipes
How to Use a Thermal Pad?
Dusty and dirty thermal pads.
- The primary steps involve obtaining the dimensions of the thermal pad according to the surface where you want to install it. Also, clean the surface thoroughly as if there are dust particles on it, it will not seamlessly fit in, and this will curtail the heat loss process.
- Once clean, lay the pad on the surface but remember to remove the protective film to expose the heat-conducting surface.
- Attach the pad to the surface, then remove the film on the upper layer to expose the underlying conducting surface. Now you have one face of the conductor (thermal pad) on the electronic component below.
- Finally, place the electric component you’re merging with the pad on top.
Thermal Pad Uses Precautions
- First, use one pad singly and avoid placing one on the other primarily because it is counterproductive. This will cause gaps in between that will affect conductivity.
- Also, whenever you use a particular heat dissipation material, use it in exclusion and don’t try to combine it with another type. For instance, never use a thermal pad with another heat transfer media, such as a thermal paste.
The thickness range of a thermal pad determines its effectiveness in dissipating heat, among other factors we have covered in this article.
Thanks for reading to the end, and we hope that you’re now fully enlightened on the essence of thermal pads.
Check out other articles for more on circuit boards and all the best in your DIY project.