Auto routing is an incredible tool for PCB design. It can save time and money, as well as reduce the risk of errors in the design. But, after completing the auto-routing process, you must remember that some manual routing is still necessary to ensure the best performance and reliability for your circuit board. In this article, we will explore the best practices for Printed Circuit Board routing after auto routing goes the distance. We will see what kind of manual routing is necessary, how to go about it, and why it’s important.
Assess the Quality of Your Auto-Router’s Work
Before you begin the process of editing or manually routing your design, you must assess the quality of the work completed by your auto-router. If your design has a lot of violations or errors, then it’s likely that manual routing is going to be necessary. To assess the quality of your auto-routed design, start by checking for errors. Make sure you properly connected all the tracks and that there are no shorts or open circuits.
Also, check the placement of the routes to ensure that they have the right width and direction. You must make sure that there are no sharp corners in the traces, as these can create stress points and reduce the reliability of your circuit. After completing this assessment, you’ll have a better idea of how much manual routing you need to complete your design.
Edit Your Design to Clean Up the Auto-Router’s Mistakes
When you auto-route your PC Board, it is important to review and clean up the results before sending it off for manufacturing. This is especially true if the auto-routing process got off center, leaving you with an excessively long or inefficient route. Before doing any manual routing, take some time to examine the auto-router’s work and make any necessary corrections.
First, check for violations of routing rules like clearance, width, and length rules. Make sure that the auto-router didn’t miss any components or create any neglected sections of traces. Then, look for any vias that you can replace with direct routing or traces that are easy to shorten to increase efficiency. You should also visually inspect the entire board layout to ensure everything looks reasonable and follows good design principles.
After editing your design to fix any errors, it is time to move on to the manual routing process. Be sure to take your time and double-check all your work before sending it off to a manufacturer. This extra effort can save you time and money down the road.
Manually Route Any Difficult or Important Signals
Manually routing signals is always the best way to ensure that you’re PCB will function correctly. Even though auto-routing can help complete most of the work, it’s important to manually route certain signals to achieve a high-quality design. This includes difficult or important signals such as the clock or power signals which require special attention.
When manually routing a signal, you must make sure that there is enough spacing between the tracks to ensure that the signals won’t be interfered with by any other nearby signals. Moreover, if you are routing high-frequency signals, you should ensure that the impedance of the track is correct for those frequencies.
Make sure that the routing of the signal is in the most direct manner possible. This minimizes the amount of noise picked up by the signal and helps reduce crosstalk between other traces on the board. Routing the high-speed signals manually also helps minimize trace inductance, which can cause ringing on the signals and increase noise levels.
By taking the time to manually route certain signals, you can ensure that your design will be reliable and high quality. Moreover, you can use techniques such as differential pairs and impedance matching to further enhance the performance of these sensory signals. You may want to consider setting aside some extra budget when designing your PCB with manual routing. As the process can be more costly than auto-routing.
Moreover, before going into production, you must double-check that all the signal routes are correct. Using software tools such as DRC (Design Rule Checking) can help identify any errors to fix them before the board goes into production. Doing this will help ensure that your final product is of the highest quality and able to meet your performance requirements.
Check Your Work For Errors Before Sending It To Fabrication
Making sure your design is free of errors before sending it to fabrication is essential for the success of your PCB. During the auto-routing process, small errors can occur and the manufacturer would reject your design. To avoid this, you should double-check your design for any errors before sending it to the manufacturer.
To check for errors, you should use a combination of inspection tools, such as visual inspections and electronic rule-checking (ERC) software. Visual inspections involve examining the traces and components on the board. Whereas the ERC software checks your design against a set of rules defined by the manufacturer.
Inspecting your board manually can help you identify issues with the routing that an auto-router could not detect. For example, if two traces cross without via, you should add one to prevent shorts and crosstalk. If you notice any errors, such as incorrect trace widths or spacing, make sure to adjust them accordingly before sending your design to the manufacturer.
Also, ensure that your design meets the manufacturer’s requirements before sending it out for fabrication. The design should be compliant with their minimum trace widths, spacing, drill sizes, and more. If the design is not compatible with manufacturing parameters, it can result in costly delays and rejections, which could easily have been avoided.
How to find that PCB design is according to the manufacturer’s requirements
You can do it by checking the size of your design. Make sure that all components fit within the PCB dimensions and have the right placement. Then, make sure that any traces or vias are wide enough for your manufacturer’s specifications. In the case of auto-routing, you must check for any clearance issues between traces. This can help you spot any potential problems before sending your board off for fabrication.
You should also review the data sheets to make sure that no noise or interference could affect the operation of your board.
By taking the time to ensure your design is compliant with the manufacturer’s requirements, you can help ensure a successful Circuit board fabrication process and save yourself from potentially costly delays down the line.
After confirming compliance, consider running some simulations to test your board’s performance under various conditions. This will allow you to see if there are any areas with crosstalk or power integrity issues. Moreover, if your board has high-speed signals on it, you may want to simulate its performance at various temperatures or levels of humidity.
Some Other Rules To Follow
You have to follow certain rules while making PCB layout as it will bring good results. So, let’s explore it further.
- The traces should have as much direct and short routing, as you can do without affecting the design.
- Try to route similar signals together, as the routing of RF and RF signals should be together. Similarly, two digital signals should also have the same route.
- Try to route vias as simply as possible, such as BGAs, ball grid arrays, or some other types of vias.
- Make sure to work according to the DFM guidelines to have perfect manufacturing.
- In the case of high-power signals, you consider impedance and choose high-quality material while routing traces or determining the length.
The design standards of printed circuit boards keep on changing due to changing technologies. But, you can’t compromise on safety and quality in this regard. The design of the PCB involves certain principles that you have to follow to have an effective product. Let’s look at those principles.
- The grid spacing should be precise
- The traces should be direct and shortest possible.
- You should be careful about power distribution
- Try not to have multiple grids
- The placement of the components should be wise as it will make design and PCB inspection easy.
- Make use of silkscreens in the best way to have more benefits.
- Always try to follow the DRC (design rule check)
- Try to avoid auto routers and go for manual work as much as possible if the budget allows you.
When you auto-route the PCB, it is important to review and clean up the results before sending it off for manufacturing. This is especially true if the auto-routing process got off center, leaving you with an excessively long or inefficient route. Before doing any manual routing, take some time to examine the auto-router’s work and make any necessary corrections.
By taking the time to manually route certain signals, you can ensure that your PCB design will be reliable and high quality. Moreover, you can use techniques such as differential pairs and impedance matching to further enhance the performance of these signals.