Monday, August 15, 2022

Miniature PCB Design Tips & Challenges

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Rachel Knox
Rachel Knox
Rachel Knox graduated from Columbia University in 2005. Rachel grew up in Canada but moved to the US after completing her school. Rachel has written for several major publications including Buzz Feed and the Huffington Post. Rachel is a community reporter, she also covers economy, business and entrepreneurial news and issues.

PCBs or printed circuit boards have applications in every electronic device in almost every industry. PCBs are thin boards with conductive pathways upon which resistors, connectors, capacitors, and other devices are mounted to communicate through the PCB.

The universality of electronic boards is impressive. Designing and manufacturing electronic boards falls under the specialty of electronic engineering. Technology is advancing at a rapid pace, and industries are finding new applications for a variety of electronic boards. The need for new electronic board designs increases daily.

In recent years, communication technologies have developed rapidly, leading to widespread mobile phone production and adoption. There’s an increased need to design PCBs that can accommodate small and high-performance components in a limited space. Wearable technology is another industry where the need for miniature boards is very high.

PCB manufacturers are navigating the challenges of designing and fabricating smaller boards while avoiding production issues like acid traps, the tombstone effect, and copper wicking. The production process of each electronic board has its complexities, and the companies that produce these boards face challenges in meeting the global market’s needs.

Manufacturing small electronic components isn’t easy, but the end goal is to help companies produce smaller products that are easier to use at a reduced cost. There are component and design limitations when trying to minimize PCB sizes further. For example, high-speed signal routing, acute trace angles, and other components need consideration when designing PCBs. Poor designs yield inefficiencies or early PCB failure.

This article looks at PCB Design tips and the methods for reducing the PCB size and the challenges facing electronic board manufacturers.

 

  1. Multi-Layer PCB designing

The design of multi-layer boards gives us more space in terms of routing. Increasing the layers increases the board’s surface space without increasing the board’s size. However, these boards add significant complexity in manufacturing, testing, and repair. Reworking circuits for a multi-layer design requires extensive testing of the prototype board.

Another advantage of multi-layer boards is the shorter design time when designing the same circuit in a single-layer or two-layer board.

Empty space on the Top and bottom layers usually filled with Ground polygons and Mid-layer 1 (the layer below top layer) is usually used for ground. Some of the critical signals also will be designed in mid-layers to be shielded by Ground and get less noise or have higher noise immunity.

Due to the higher cost of designing multi-layer boards, the final cost must be calculated before changing the board and considered in order to finally produce a suitable product.

  1. Copper thickness management

A thick stream of copper is usually used for high currents, but it takes up a lot of space on the board. Increasing the thickness of the copper is a great option to reduce the size of printed circuit boards effectively.

PCB copper usually falls between 0.5 oz to 4 oz per square foot. As the copper thickness increases, a higher current can pass through the circuit. But it’s important to note that higher oz PCB’s cannot accommodate low pitch pins and components.

  1. Select smaller component Package size

Selecting components for PCBs is one of the most critical parts of designing electronic boards. There are many component options on the market, so PCB designers can find the exact components to fit their board. For example, a resistor with the same characteristics may be offered in multiple sizes. Way more design configurations are possible for PCBs because of these options.

In most cases, choosing larger packages makes the job easier for the board manufacturer, but using smaller parts means a board can be smaller. Again remember that smaller board components add certain precision requirements and challenges to the design process.

component Package size

Another drawback of smaller components is the power rating limits. Packets smaller than 0603 (numerical code for component sizes) can withstand much less current than 0805 or 1210, so designers must consider this.

  1. Use the new generation of compact connectors

Connectors usually take up a lot of space on the board. If the current and voltage required in the design can allow the use of a new generation of connectors, this is a preferred design choice. These connectors are more compact and can help miniaturize the board.

  1. Use of resistance networks

In the microcontroller-based design, resistors are placed in the circuit to protect the microcontroller against the high current. In some cases, up to 16 resistors. This large number of resistors takes up a lot of space on the board. Resistance networks are recommended to reduce the number of resistors and allow the board to be smaller.

  1. Using Stacked Packages Instead of Standard Packages

Electronic circuits may require multiple transistors or, in some cases, more than two MOSFETs, which will take up more space. There are different package options in which several components are placed in one package and are equal in size to one component. Using stacked packages is also more cost-effective compared to using separate components.

Wrapping up PCB Design Challenges

PCB design and manufacturing electronic boards is one of the most critical processes for many industries. In recent years, technology has advanced rapidly, especially in the smartphone, wearable technology, and medical industries. Companies desire to produce smaller products, and tiny gadgets require tiny components. In response, electronic components have been minimized to aid in designing and manufacturing miniature boards.

Miniature boards present new challenges during design and fabrication. Due to the small size of the boards and the difficulty of changing or repairing them, the design and component selection is critical. All stages of production are done to high precision, backed up by engineering calculations so that the performance of the electronic circuit is maximized.

Author: Sara (Fakhri) Siahkar IoT Specialist @ Arshon Technology Inc.

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