PCB Routing Essentials for the Modern Designer

The approach towards PCB designing and manufacturing  has changed drastically over the years. With the upgrade in PCB technology and changing ways of PCB manufacturers in USA, the designers have wider scope in accomplishing multiple challenges and have desired PCB routing. Earlier the PCB routing was simpler and had fixed spacing in comparison to the width. In today’s time, designers need to be thorough with modern tools to achieve various constraints. 

In this article, we will have a look at a few techniques that are essential for the modern designer. These techniques are changing the era of PCBs and it's the right time to adapt to the change in order to stay relevant. But before that, let’s have a look at the basic understanding of the PCB design workflow. 

Workflow of PCB Design:

Here’s a stepwise sequence for the PCB design:

1. Ensure to verify the core component as per its long term availability and choose the one that has a pin-compatible alternative. 

2. Create schematics based on the engineering requirements. 

3. Form a blank PCB and start building the stackup (If needed). 

4. Import the footprint of the actual component data into the PCB layout from schematics. 

5. Make sure to review the placement in order to achieve accurate data. 

6. Route the traces between the components as per the connections

7. Now clean up the layout.

8. Now perform a final review and prepare design outputs. 

Now that you are aware of the basic workflow of PCB design, it’s time for us to view the different tools/techniques that PCB designers must utilise.

Differential Pair Routing 

Single-ended routing is when a plane ground provides a return path for the signal to flow. There are a few problems with single-ended routing which are- electromagnetic interference, crosstalk and low signal-to-noise-ratio. 

While differential routing requires two signals with opposite polarity yet same magnitude that transfer a single data signal from another, the most exciting part about differential pair routing is that the interference will exist equally in both signals in a way that the receiver can cancel out the signal. To ensure optimal performance from differential pair routing, you need to take care of trace width, spacing and other performance parameters. 

Routing Complex ICs

To understand the setup and rules of routing complex ICs you need to understand the base configuration. The complex ICs require smaller trace widths, done by squeezing compact routing in multiple layers to achieve the desired miniaturization. The routing of complex ICs is a high-speed constraint and requires a specified schematic. Here, you need to ensure that the entire ground path is kept really close to the receiver that offers you the lowest data bit. 

Utilization of Autorouter

To ensure optimum utilization of resources with precise time management, automated PCB routing comes into the picture. While working on a larger board, it becomes really complicated to trace routing manually. With the help of autorouter,  you can have the work done in less time. There are multiple PCB design tools with autorouter feature and CAD systems which are relatively easy to use and deliver superior results. 

If you are now convinced to have an autorouter, you need to understand and learn the important rules and constraints that derive net classes as per the trace widths and spacing in each board. With a proper understanding of the rules, one can achieve the desired design. You will have to avoid running traces over the component placement and routing. Also, you can run a routing cleanup before reviewing the setup. 

Design Rules and Constraints

There are multiple design rules and constraints that have to be followed in order to have the desired analogue. The constraint manager helps you in taking control over the technicality of the design. 

Added tips and techniques for PCB routing 

There are a variety of PCB routing tips that will differ from analogue parts, terminal components, connectors and more. Have a look at some tips:

• You need to consult your PCB manufacturer to have specified width and spacing requirements. 

• You will need to have power and wider ground connections to ensure the smooth flow of current. 

• To avoid noise in the circuit and reduce any kind of inductance, you need to keep the power and ground close to each other. 

• The power supplies will have multiple trace widths depending on the circuit. 

• If you are working with high-speed traces you must have large spacing to prevent any kind of crosstalk. 

Now that you have discovered the routing essentials, we can conclude that having advanced routing tools and techniques can improve your designs in a humongous way. Even the most difficult designs can be accomplished when you use the right rules and tools. Both manual and automatic approaches are great in their aspects but you can walk with the latest technology to stay updated and create well derived PCB designs as per your requirements. 

When it comes to empowered technology PCB Power Market offers custom fabricated PCBs. Visit us at usa.pcbpower.com and keep yourself updated with the latest market trends and tips.

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