In the modern electronic world that pursues high-density, multi-layer interconnection, single-sided boards still occupy an irreplaceable position in many fields due to their ultimate simplicity, unparalleled cost-effectiveness, and reliable manufacturing process.

When we disassemble a simple electronic toy, an old radio or even a smart home remote controller, you will find there is one piece of green board with only one side circuit on it, that is the single-sided PCB, the most classic and basic part in the PCB world.

I. What is a Single-Sided PCB?

A single-sided PCB, apparently, is a printed circuit board with only one layer of conductive copper foil on it. All the electronic components are assembled on one side of the board, while the circuit is connected on another side with an etching process.

There are three main parts in a single-sided PCB;

-. Base material: normally FR-4 fiberglass epoxy resin to offer mechanical support

-. Conductive layer: the copper foil on one side of the PCB, the thickness is 1oz(35um) or 0.5oz(17.5um)

-. Protective layer: solder mask ink(normally is green) and silkscreen marks

The biggest feature of single-sided PCB is easy design with low manufacturing cost and short lead time, which makes single-sided PCB become the first option for massive consumer electronic products.

II. Manufacturing Process for Single-Sided PCB: Simple But not Easy

The manufacturing process for a single-sided PCB is relatively simple, but every process needs to be accurately controlled.

Material Preparation: Choose a suitable base material: FR-4, CEM-1, and XPC are the most common materials. Different materials have different performance and price ranges.

Pattern Transfer: The designed circuit pattern is transferred to the copper-clad board through UV exposure, which is a critical step in determining the circuit accuracy.

Etching: A chemical etching solution (usually acidic copper chloride or alkaline ammonia) is used to remove the unwanted copper foil, leaving the desired circuit pattern.

Drilling: Using CNC drilling machines to drill assembly holes and plug-in holes, the hole diameter is normally over 0.8mm.

Surface Treatment: Choose the surface treatment according to the application requirement, for example, HASL and OSP.

Solder Mask and Silkscreen: The solder mask can prevent the short circuit during the soldering process, and silkscreen legends can indicate the components’ location and direction to simplify the soldering process.

Test & Inspection: Perform electrical test and visual inspection to make sure there is no open circuit, short circuit, or other defects.

III. Single-Sided PCB VS Double-Sided PCB VS Multilayer PCB: How to Choose?

Understanding the positioning of single-sided boards requires comparing them with other types of PCBs:

Feature	Single-Sided PCB	Double-Sided PCB	Multilayer PCB
Layout density	Low	Medium	High
Manufacturing cost	Lowest	Medium	High
Design complexity	Simple	Medium	Complex
Manufacturing cycle	Short	Medium	Long
Suitable Frequency	Low frequency	Medium frequency	High frequency
Typical application	Consumer electronics and simple control	Industrial control and telecommunication devices	Smartphones and computers

The key point of choosing is to balance the performance requirement and cost control. If the circuit doesn’t have a high-density interconnection requirement and the cost is very sensitive, a single-sided PCB is the best choice.

IV. Five Big Advantages of Single-Sided PCB

1. High Cost-Effectiveness

The material cost, manufacturing, and fabrication cost of a single-sided PCB are the lowest among all the PCB types. For mass production products, if it can save even a cent for a board, the overall saving is very impressive.

2. Mature Manufacturing Process

After decades of development, the manufacturing process of single-sided PCB is very mature, the pass rate is high, with a steady manufacturing rate, and almost all the PCB factories can arrange the fabrication skillfully.

3. Easy & Fast Design

Using simple EDA tools will finish the design; the design cycle is short and very easy to update. A single-sided PCB is a great option for rapid product development and iteration.

Using simple EDA tools will finish the design; the design cycle is short and very easy to update. A single-sided PCB is a great option for rapid product development and iteration.

4. High Reliability

Due to the simple structure, there are few failure points, and the reliability is relatively higher. Without through holes and complex interconnect, the potential failure risk is greatly reduced.

5. Easy to Repair

All the components are assembled on the same side, which brings much convenience for inspection, repair, and changing components, which greatly lowers the after-sales service cost.

V. The Limitations of Single-Sided PCB

A single-sided PCB is not a panacea; it also has its limitations.

-. Layout density limitation: the circuits have to be on one side, and can not realize complex circuit interconnection.

-. High-frequency performance limitation: a single-sided PCB is not suitable for high-frequency or high-speed signal applications

-. Dimension limitation: complex circuits always require a larger size

-. Function limitation: shielding and complex power distribution cannot be achieved by a single-sided PCB.

Understanding the above-mentioned limitations will be helpful in making the right choice when designing.

VI. The Typical Applications of Single-Sided PCB

Though the technology is developing all the time, single-sided PCBs still have wide applications in the following areas:

1. Consumer Electronics

-. Remote controller, calculator, and electronic toys

-. Small appliances control board(rice cooker, microwave oven, washing machine)

-. LED lighting products

2. Industrial Control

-. Simple control board and sensor interface board

-. Power supply monitor equipment, relay control board

3. Automotive Electronics

-. Control module and simple sensor interface

-. Sound system and lighting control

4. Educational Experiment

-. Electronic education experiment board

-. Student intelligence development experiment board

VII. Single-Sided Design Techniques and Best Practice

1. Layout design points

-. Try to avoid cross-wiring and use jumpers when necessary.

-. The power supply line should be as wide as possible to lower the voltage drop.

-. Signal lines should avoid long parallel distances to reduce crosstalk.

2. Components Layout Strategy

-. First, place the connectors in a fixed location.

-. Group and layout related components by functional modules.

-. Considering the heat dissipation requirements, heating components should be placed separately.

3. DFM(Design for Manufacturability) Consideration

-. The trace width and spacing should be better over 6mil, or the manufacturing cost will be higher accordingly.

-. The pad size should be at least 0.4mm larger than the pin.

-. Save enough waste tabs and tooling holes.

VIII. The Future of Single-Sided PCB: The Modern Iteration of Traditional Technology

Despite the emergence of new technologies, single-sided PCBs won’t be eliminated; it is on the way to continuous development.

1. Material Innovation

New types of materials, like metal substrate and ceramic substrate, they expanded the width of single-sided PCB application in high-power and high thermal conductivity areas.

2. Technology Improvement

More precise etching technology makes it possible for a single-sided PCB to realize thinner trace width and spacing, and improve the trace density.

3. Design Tools More Intelligent

The automatic routing and optimization algorithms of modern EDA tools can maximize the utilization of the routing space of a single-panel board.

IX. Actual Case Analysis: How the Single-Sided PCB Saves Cost

One home appliance company manufactures an intelligent fan control board. At first, they used a double-sided PCB; the manufacturing cost for each piece is 12RMB. After redesign and optimization, they used a single-sided PCB, and;

-. Material cost decreased 40%.

-. Simplifying the manufacturing process, the pass rate increased 5%.

-. Overall cost went down to 7RMB for each piece.

-. Annual production 500,000 pcs, saving 2.5 million RMB in costs every year.

This case demonstrates the giant value of single-sided PCBs in cost-sensitive products. Moreover, using single-sided PCBs in such products can lower the maintenance cost in future service.

X. Conclusion: Classics Never Go Out of Style

Today, with the rapid development of electronic technology, single-sided PCBs may not be noticeable like multilayer PCBs or HDI PCBs. However, it still has an unreplaceable position as the basic and classic part in the PCB area.

It always reminds us that when we pursue technological innovation, we should not ignore the value of simplicity and cost-effectiveness. The best design is not always the most complicated, but the one that best suits the product’s needs.

Whether you’re a beginner or an experienced engineer, understanding and applying single-sided PCB technology will allow you to create cost-effective and reliable product designs in the right situations. This is precisely the reason why single-sided PCBs are so popular: this seasoned veteran is able to stand firm in modern electronic design.

Next time, when you design a simple circuit, maybe you can consider whether the design can be realized with a single-sided PCB? Perhaps you will find that the easiest solution can be the best solution as well.

Let’s talk about PCB today!