Can I design a double circuit board

The Top 5 PCB Design Guidelines Every PCB Designer Should Know

David Marrakchi
| & nbsp Created: August 21, 2017 & nbsp | & nbsp Updated: September 25, 2020

What is the key to designing a circuit board that is realistic on paper and in reality? Learn below the 5 most important guidelines with which you can develop your next PCB in a manufacturable, functional and reliable way.

The Top 5 PCB Design Guidelines Every PCB Designer Should Know

At the beginning of a new design, PCB design can easily become a sideline if you spend most of your time circuit design and component selection. But ultimately, if you don't invest enough time and focused effort into a good PCB design, you and your manufacturer can quickly create problems when transferring a design from the digital to the real world. So what is the key to designing a circuit board that is realistic on paper and in reality? Learn below the 5 most important guidelines with which you can develop your next PCB in a manufacturable, functional and reliable way.

Rule 1 - Fine-tuning your component placement when laying out your board

The component placement stage in your PCB layout process is both an art and a science that requires you to strategically weigh the space available on your board. This process can be challenging because the placement of your components will determine how easy your board will be to make and how well it will meet your original design needs.

Although a general guideline states that the components should be placed in the basic order of connectors, live circuits, precision circuits, critical circuits, etc., there are also a number of specific guidelines, such as:

  • Alignment. You should definitely place similar components in the same direction to ensure an efficient and error-free soldering process.
  • placement. Avoid placing components on the solder side of the board where they would be behind coated push-through components.
  • organization. We recommend placing all of your SMDs on the same side of the board and all through-hole components on top of your board to minimize the number of assembly steps.

One final PCB design guideline to keep in mind, if you are using mixed technology components (thru-hole and SMT components), manufacturers may need a separate process to assemble your board, which increases your overall cost.

Quality Alignment of chip componentsBad Alignment of chip components

Quality Placement of components Bad Placement of components (shading)

Rule 2 - Placement of your power, ground, and signal traces

Once your components are in place, you can lay the conductor tracks for the power supply, signal transmission and ground connection so that your signals can take a free and smooth path. Here are some guidelines for this phase of your layout process:

Alignment of the power supply and ground planes

It is always recommended to arrange your power supply and ground planes on inner layers, symmetrically and centered. This will prevent your board from bending, which will also affect the correct placement of your components. To power your ICs, you should use common lines for each supply, make sure that the conductors are robust and wide, and avoid daisy-chaining the supply lines from one component to the other.

Connecting the signal conductors

Next, your signal lines need to be connected according to your schematic specifications. It is recommended to always lay the conductor tracks as short as possible and directly between the components. Should your component placement force the conductor path to be routed horizontally on one side of the board, you should always place the conductor paths vertically on the opposite side.

Determination of the network widths

Your design will likely require different networks with a wide range of currents. The latter determine the network width. With this basic requirement in mind, we recommend 0.010 "width for analog and digital signals with low currents. If your tracks carry more than 0.3 amps, the network should be wider. This free track width calculator simplifies this process.

Preferred routing: (arrows show the direction of solder migration)

Not preferred routing: (arrows show the direction of solder migration)

Rule 3 - Keep everything nicely separated

You have probably already experienced how high voltages in power supply circuits and current spikes can interfere with low voltage and current regulator circuits. To minimize this interference, please follow the guidelines below:

  • separation. It is essential that you keep the grounds for power supply and regulation separate for each power supply stage. If you really need to merge these together on your PCB, it's best to do that towards the end of your supply path.
  • placement. If you have placed your ground plane on the middle layer, you should definitely create a path with low impedance in order to minimize the risk of interference from the power supply circuit and to protect your control signals. The same guideline can be used to keep the grounds separate for digital and analog circuits.
  • coupling. To reduce the capacitive coupling due to large ground areas and the lines running above and below, only analog lines should cross the analog ground.

Example for the separation of components (digital and analog)

Rule 4 - Combat Heat Problems

Has it ever happened to you that your circuit has deteriorated or even damaged your circuit board due to thermal issues? This problem affects many designers who do not plan for heat dissipation. Here are some guidelines to avoid heat problems:

Identification of problematic components

The first step is to consider which components on your circuit board give off the most heat. To do this, look in the data sheet for your components under "Thermal resistance" and then follow the recommended guidelines for dissipating the heat generated. Of course, you can also install heat sinks and fans to cool the components, but you should also place critical components as far away as possible from heat sources.

Adding thermal reliefs

Adding "Thermal Reliefs" is great for developing a manufacturable board. They are also of essential importance for the wave soldering of assemblies with a high copper content and multi-layer circuit boards. Because it can be difficult to maintain the process temperatures, it is always recommended to use thermal relief for push-through components in order to simplify the soldering process as much as possible. In this way, you slow down the speed at which heat can pass through the layers of the component.

In general, you should always provide a thermal relief pattern for vias or holes that are connected to ground or power supply surfaces. In addition to thermal relief, you can also place teardrops where the conductor tracks converge with pads to provide more supportive copper or metal. This reduces the mechanical and thermal stress.

Typical thermal relief pattern

Rule 5 - Review Your Work

It's all too easy to get overwhelmed by the effort of putting all the pieces together at the end of the design project. Double and triple checking of your work for errors can make the difference between success and failure in the manufacturing process.

To support this quality control process, it is always recommended that an electrical rules check (ERC) and a design rules check (DRC) be performed first to ensure compliance with all specifications. With these two systems, you can easily enforce rules for gap widths, trace widths, common manufacturing structures, high speed requirements, and short circuits.

If the ERC and DRC give good results, you can then check the routing of each signal and make sure you haven't missed anything. To do this, you need to go through your circuit diagram line by line. And of course you need to use the probing and masking functions of your design tool to check that your PCB layout matches the schematic.

It is best to double-check your rules for design, PCB and specifications

Conclusion on the board design

That's it - our top 5 PCB design guidelines that every PCB designer should know. If you follow this small list of recommendations, you will be well on your way to a functional and manufacturable board and a truly high quality PCB.

Good PCB design methods are critical to success. They form the foundation for building and solidifying a practice of continuous improvement in all of your design disciplines.

Would you like to find out more best practices for developing a circuit board that makes it into production at the first attempt? Then watch our Webinar on Design for Manufacturing - Maximize Your PCB Production Yield - or try these PCB design guidelines with our top software now.

With the new Altium 365, there is also a cloud platform available with which you can ensure even better communication, from anywhere.

About Author

About Author

David currently serves as a Sr. Technical Marketing Engineer at Altium and is responsible for managing the development of technical marketing materials for all Altium products. He also works closely with our marketing, sales, and customer support teams to define product strategies including branding, positioning, and messaging. David brings over 15 years of experience in the EDA industry to our team, and he holds an MBA from Colorado State University and a B.S. in Electronics Engineering from Devry Technical Institute.