Choosing a double-sided PCB may help increase the efficiency of your next project. At PadPCB, we frequently fabricate double-sided PCBs for a vast range of applications, from industrial controls to consumer electronics.
Take a moment to learn more about double-sided PCBs, including common applications and the benefits of using a circuit board with two layers.
What is a Double-Sided PCB?
A double-sided printed circuit board (PCB) features copper traces on both sides of the board instead of a single side. The two copper layers double the surface area to work with when planning your circuits, as the traces can crossover from one side to the other.
Conductive holes can be added to allow circuits from one side to reach the other side. This gives you the flexibility to solder surface mount devices (SMDs) and through-hole components and either side.
Double-sided PCBs are also called double-sided plated thru (DSPT) circuit boards, double-layer PCBs, and two-layer PCBs. A double-sided PCB is not the same as a multilayer PCB. A multilayer PCB includes a minimum of three conductive layers connected via copper-plated holes.
How Do You Make a Double-Sided PCB?
Making a double-sided PCB requires you to create circuit designs for both sides of the board. The two sides must align, as components are soldered to both sides.
When it comes to manufacturing double-sided PCBs, the boards are made using several layers of material. Each side includes a solder mask over a copper layer. The solder mask protects the circuit board. It is often green.
The thickness of the copper layer depends on the needs of the circuit. If your design requires very high power with a high current, your PCB may require a thicker layer of copper.
A silkscreen may be added to the top of the solder mask to provide visual aids to those working on the boards, such as symbols and numbers for the placement of capacitors, resistors, and transistors.
A dielectric layer, or substrate layer, is sandwiched between the two sides and acts as the base of the board. Dielectric materials are poor conductors of electricity, which is why they are used in the center of the PCB.
Epoxy resin is the most common substrate for PCBs. Other dielectric materials include plastic, porcelain, glass, and certain metal alloys. Epoxy resin with fiberglass and plastics makes PCBs more flexible while porcelain and glass are more rigid.
These layers are also found in single-sided PCBs. However, a single-sided PCB includes the copper layer, solder mask, and silkscreen on a single side instead of both.
When Should You Use Double-Sided PCBs?
A double-sided PCB is a suitable choice for a wide range of applications. In fact, double-sided PCBs are the most common type of circuit board. Most modern electronics include double-sided circuit boards.
Some of the appliances and electronic devices that are most likely to use double-sided PCBs include:
- Power supplies
- HVAC control systems
- Printers
- Traffic systems
- Cellphones
- Car dashboards
- LED lighting systems
- Amplifiers and sound systems
Almost any device with complex circuitry and limited space is likely to include a double-sided PCB. Single-sided circuit boards are more common with older radio equipment, camera systems, and calculators. These appliances often feature simpler circuits with fewer components.
Some electronic equipment also supplies more space for the circuit board, such as the inside of an arcade cabinet or vending machine. The extra space allows manufacturers to add larger boards with more spacing.
A double-sided PCB may make more sense for your project if you have a complex design, many components, or limited space. Using two sides makes it easier to plan your routes. It can also limit the size of the board, which is useful when working with a small enclosure.
Benefits of Double-Sided PCBs
Double-sided circuit boards offer many advantages over single-sided PCBs. Here are a few of the benefits of using a double-sided PCB:
- More cost-effective compared to single-sided PCBs
- May help reduce the size of the board
- Reduces the complexity of the circuitry
- Suitable for sourcing currents
- Offers greater flexibility for PCB designs
A double-sided PCB can cost more compared to a single-sided PCB of the same dimensions. However, you also double the working area of the board, which can result in a more cost-effective solution.
Using two sides of the board may also help reduce the size of the board. Reducing the size of the board can further limit the total cost of fabricating your custom PCBs.
A double-sided PCB can also reduce the complexity of the circuits. You gain more space for routing. In some cases, a double-sided PCB is the only viable option for keeping traces from getting in the way of each other. You can add components to either side, which allows you to work around traces.
You can also limit the density of the circuitry, allowing you to space components further apart. Proper spacing can minimize electromagnetic interference (EMI) and ensure sufficient cooling for components that heat during use.
With a double-sided PCB, the bottom layer is occasionally used for grounding the circuit. You can use the bottom layer to sink or source currents while leaving the upper layer free to design your circuit.
Having the option to add routes and components on either side of the board gives you more flexibility compared to using a single-sided board. You have greater freedom to create a design that suits the needs of your project rather than limiting your possibilities.
PadPCB is ready to start fabricating your custom double-sided circuit board. We offer fast turnaround, with products shipped on time every time.