How to Reduce the Size of a Printed Circuit Board (PCB)
Are you struggling to fit all of your electronic components onto a printed circuit board (PCB)? Do you find yourself constantly redesigning the layout to no avail? The size and complexity of a PCB can quickly become overwhelming, especially for those new to electronic design.
A printed circuit board serves as the foundation for electronic devices, providing a platform for the components to operate on. As technology advances, the number of components and the complexity of circuits increases, making it even more challenging to fit everything onto a small PCB.
Fortunately, there are techniques and strategies that can be employed to reduce the size of a PCB without sacrificing functionality. In this article, we will explore the various ways to optimize your design, including component selection, layout, and utilizing advanced technologies.
Table of Contents
Why PCB Size Reduction Matters?
Size reduction is important for PCB design for a variety of reasons, including:
- Reduced costs
- Device size restrictions
- Increased portability
- Greater design flexibility
- Better performance
Reducing the size of a PCB may provide cost savings. Larger boards require more materials, which increases manufacturing costs.
A smaller PCB is important when designing compact devices, including wearables and small medical devices. Small electronics are likely to have size restrictions. Shrinking PCB dimensions may be necessary to make the board fit in the required housing.
Reducing the size of a PCB can also result in a more portable design. Your final design may be smaller, lighter, and easier for users to carry.
Creating a smaller PCB gives you greater flexibility during the design process. You may gain more options when it comes to component placement and routing, making it easier to create an efficient design with improved thermal management.
Miniaturizing printed circuit boards can also lead to better performance. A small PCB is likely to have shorter signal traces and less distance between components.
Shorter traces can help reduce electromagnetic interference (EMI), reduce transmission time, and prevent signal loss. These benefits help maintain the integrity of the data signal, which is often necessary for devices that feature high-speed transmissions.
Effective Strategies for Reducing PCB Size
Miniaturizing printed circuit boards involves optimizing the layout and design to make the best use of available space, resulting in a smaller footprint. Here are the most effective PCB size optimization strategies.
1. Using Multilayer PCB to Reduce Track Space
Using a multilayer design can help with miniaturizing circuit boards. A multilayer PCB can reduce track space and component spacing.
It becomes easier to create the routing for a smaller board when using a multilayer design. You have more space to work with on each layer, which can prevent overcrowding and cross-chatter.
Using a multilayer design can shrink the width and length of the board. It also increases the height, which may be a factor when designing a PCB for a small device.
A multilayer PCB also tends to cost more compared to a single-layer or dual-layer PCB. However, the board is likely to have smaller overall dimensions, which can help offset the costs of the multi-layer design.
When using a multilayer design, your PCB is likely to include via holes to connect the layers. Using penetrating vias instead of blind holes can help limit the cost of manufacturing a large quantity of PCBs.
2. Changing Copper Thickness to Manage Thermal Issues
Increasing the thickness of copper traces can help with the management of thermal issues. A thicker copper trace can transfer more heat, reducing the need for heat sinks. Eliminating heat sinks saves space, helping to reduce the size of the PCB.
Along with thicker copper, you may also consider using heavier copper. Copper for PCBs is commonly available in weights ranging from one ounce to ten ounces. Finding the right balance between thickness and weight can help shorten traces and keep the board small.
One ounce is the most common thickness for copper traces, as it can handle moderate current levels. Devices that require higher current typically include two-ounce copper traces.
Increasing the weight of the copper to two ounces allows you to reduce the thickness of the trace by half without sacrificing heat dissipation.
After choosing the thickness and weight of the copper, optimize the trace routing to save space. You can decrease the trace width and spacing between traces. However, you need to avoid placing the traces too closely, as tight spacing can increase the risk of crosstalk and EMI.
3. Changing the Component Package Selection
Using smaller components or switching to a smaller package size can reduce PCB size. Electronic components come in a wide range of package types and sizes. Some package types offer a smaller footprint compared to others.
For example, some surface mount packages include pins that extend from the package, while others have pins located on the underside of the package. Choosing a package with pins on the underside of the component may save space.
Review each of the integrated circuits and other major components on your PCB. Determine if any of the selected components are available in smaller packages or form factors.
If your prototype contains through-hole components, consider switching to surface mount. Surface mount devices (SMDs) take up much less space compared to through-hole components, especially when mounting resistors and capacitors.
After choosing the smallest package, examine the datasheet to determine the smallest possible footprint. The default footprint is often larger than you need to mount the component.
Using a smaller footprint may reduce the space needed by a millimeter or two. If you repeat this process, you may save quite a bit of space across the entire board.
You should also remove testing components before finalizing your PCB design. Extra headers and pads are often necessary during the prototyping process for debugging. However, these components also take up unnecessary space for the final design.
4. Using Smaller Resistor and Capacitor Sizes
Along with using smaller ICs, switching to smaller resistors and capacitors may help reduce PCB size. Many prototypes are completed using 1206 or 0805 surface mount resistors and capacitors. Switching to 0603 or 0402 resistors and capacitors can save significant space.
A 1206 SMD resistor should measure about 3.1 mm by 1.6 mm. A 0402 SMD resistor measures 1 mm by 0.5 mm, requiring about 1/9th of the space.
Using smaller resistors and capacitors should not be a problem when using automated tools for PCB manufacturing. A pick-and-place machine can handle smaller packages, including 0402 SMD resistors and capacitors.
Keep in mind that smaller resistors and capacitors are likely to have lower temperature thresholds. Avoid using resistors and capacitors that are too small to handle the temperatures produced by your board.
5. Using Stacked Packages Instead of Standard Packages
Using stacked packages can help save space compared to using standard packages. A stacked package combines multiple components into a single package, which often results in a smaller footprint. You can find stacked packages for resistors, capacitors, and transistors, including MOSFETs.
For example, a resistor network package should save space compared to using a series of resistors with equal values.
Using modules that combine packages or components is another solution. For example, if your PCB requires Wi-Fi and Bluetooth connectivity, consider using a Wi-Fi/Bluetooth module instead of separate components.
Summary
Miniaturizing printed circuit boards can result in cost savings, increased portability, and better overall performance.
Some of the most effective strategies for reducing the size of a PCB involve switching to smaller components, using a multi-layer design, and increasing the thickness of the copper traces.
Optimizing the trace routing, using stacked packages, and using heavier copper can also help create a more space-efficient design.
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