What Is a Single-Layer Metal Core PCB?

Single-layer Metal core PCB is the simplest Metal Core PCB(MCPCB), which is composed of a copper foil circuit layer, a thermal conductivity layer (usually prepreg), and an aluminum or copper substrate(base). The aluminum or copper substrate(base) exhibits excellent thermal conductivity, allowing rapid transfer of heat away from critical components such as LED chips, and ICs on the circuit board. In comparison to traditional FR-4 PCB, with the same thickness and line width, an aluminum or copper substrate can carry higher electrical currents. These excellent properties make it suitable for applications requiring high power or need to generate a significant amount of heat, for example: LED lights, industrial power equipment, cars, audio devices, and so forth.

The structure of a 1-layer aluminum or copper substrate PCB is illustrated below.

Structure:

1.Circuit layer:

The circuit layer, typically made of electrolytic copper foil, through etching process to form a graphic circuit layer used for the assembly and connection of devices. In general, the copper foil thickness is 1oz, 2oz, 3oz, and it can be up to 10oz. It also can be customized based on customer requirements. In Best Technology, the minimum line width and spacing of metal core PCB is 4/4 mil. Thicker copper corresponds to larger line widths and spacing, and within allowable limits, even thicker copper foils can be achieved through processes such as copper plating. Besides, compared to traditional FR-4, metal core boards can carry higher currents at the same thickness and line width.

2.Thermal Conductivity Layer:

The thermal conductivity layer is in the middle of the circuit layer and aluminum base since the circuit layer and the substrate both are metal. This layer is composed of a prepreg composed of polymer (mainly epoxy resin) filled with high thermal conductivity and high insulation material, so it also be called a dielectric layer or insulation layer in other readings or articles.  The dielectric layer in metal core PCB mainly serves to prevent electrical breakdown between electrodes under equipotential conditions, ensuring the stability and functionality of electronic components. The commonly used conductivity of the dielectric layer is 1W, 2W, and 3W, different conductivity corresponds to different thickness ranges, for example, the thickness of 1W material is around 75-100um, and 2W is 100-125um... The higher thermal conductivity means quicker heat transfer capability and better heat dissipation performance.

3.Metal Base Layer:

The aluminum or copper core is the common base material of a metal core PCB. The final thickness of a single-layer metal core PCB primarily depends on the thickness of the metal base. The common thicknesses include 0.8mm, 1.0mm, 1.2mm, 1.5mm, 1.6mm, 2.0mm, and 3.0mm. The thickness of the aluminum base or the copper base, combined with the thermal conductivity of the insulation layer, determines the heat dissipation effectiveness of the whole metal core circuit board.

Advantage:

Lightweight design： Compared to other common PCB solutions, single-layer metal core PCB is slightly lightweight. It is worth considering when some devices with the requirement of weight.
Relatively low cost: Compared to some multi-layer aluminum boards, single-layer aluminum board has a lower cost. So, it could be chosen when your product is sensible to cost.
Easy to manufacture: Relative to two layers and multi-layer Metal core PCB board, single-layer metal core PCB board is relatively easy to manufacture; it would lessen the time and difficulty of cutting and punching the board.
Widespread application: due to its low cost and easy production process, single-layer metal core PCB board has wide use in many industries, such as introduced below.

Application:

LED lighting: single layer metal core PCB is always used in LED Lighting fixtures because metal core PCB is good at dissipation.
Power module: Because with some IC chips and materials working, there is always a lot of heat generated. To keep a suitable temperature, it is also considered for engineers to use a single-layer metal core PCB.
Automobile electronics: In the industry of automobile, single-layer metal core PCB usually be used in some high heat dissipation required modules, such as engine control modules.
Telecommunication device: It is common to see the single-layer metal core PCB in some devices of telecommunication. Especially to say some devices need a compact design and high heat dissipation.

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