Metal core PCBs, also known as MPCBs, are very popular, and they are chosen over the regular FR4 PCBs due to certain unique benefits that they offer. In the last post, we have broadly described these PCBs, their advantages, types, and applications. Single layer PCBs are one of the most popular types of metal core PCBs available for purchase. In this post, we will discuss this type in detail.
Brief Introduction to Single Layer Metal Core PCBs
A layer of single sided PCB features the following composition
- Base Metal Layer – This is usually a copper alloy or an aluminum.
- Dielectric Layer – This is a non-Conducting Layer
- Copper Circuit Layer
- Solder Mask
- IC Components
In this circuit, a thin layer of electrically insulating dielectric is laminated between a copper foil, and a metal base. The copper foil is usually etched in a desired pattern. The base metal layer provides mechanical integrity to the PCB, and aids in heat distribution, as well as heat transfer to a heat sink, ambient air, or to the mounting surface. Aluminum is the most preferred metal used for metal core PCBs because it is cheaper than copper alloys. The dielectric provides electrical isolation, and aids in heat transfer from the components, as well as the foil to the metal plate. In short, the metal layer along with dielectric, takes away heat from the PCB. This is the reason why single layer MPCBs are used with many wire and chip components and surface mount. These PCBs provide excellent thermal resistance than the regular FR4 PCBs.
Benefits of Single Core MPCBs
As suggested before, most MPCBs are made from an alloy of copper or aluminum. Here we will discuss few benefits of single layer metal core PCBs comprising a layer of copper or aluminum.
- Thermal Transfer and Heat Dissipation: Generally, single core base metal PCBs have better heat dissipation, as well as heat transfer characteristics than FR-4 PCBs. Copper has a better thermal conductivity than aluminum, and dissipates heat faster in air. However, aluminum is considered perfect in many applications because it has a less dense structure than copper, which when removed from heat will cool faster, too. Hence, aluminum has better heat dissipation than copper.
- Less Prone to Distortion: Aluminum or copper layer are less prone to heat induced distortion when compared to FR-4 PCBs. This makes them ideal for high switching power applications.
- Easy Implementation for Higher Density Designs: Single layer aluminum or copper backed PCBs are used in high density designs because they have better thermal conductivity than fiberglass PCBs.
The surface finishing of these PCBs is usually done in immersion gold, OSP, and HASL, which helps improve their mechanical characteristics. Most PCB assembly services will provide you single layer metal core PCBs with copper or aluminum base layer. You can always check with them to understand the benefits of each base layer in your application. Additionally, you can opt for two layers, double sided, and multi-layer MPCBs. We will discuss each of them in detail in the upcoming blogs.