Remember when we were kids and our parents gave us permission to do something fun but first we had to finish our chores? Now, taking out the garbage, folding clothes, and mowing the grass I’d prefer compared to budgeting for vacations or renovating bathrooms. Getting the chores completed lets me move on to something that is at least significantly more convenient and in many cases more fun.
When I’m designing, I have similar chore preferences and priorities; I personally love to route traces—I’d spend all day doing unnecessary auto-routing clean-up just to keep on routing. The chore that always got in my way was placing components; in hindsight, placing components really isn’t that bad, but it still feels like a chore to me. Having good library parts and helpful component constraints will make your placement more efficient. Utilizing all of the placement utilities available to you will get you to the next step and make your placement process even more efficient. But the thing to keep in mind is: if a particular task feels more like a chore than anything else, it’s usually because you’ve got the most room to improve your process there.
For Proper PCB Component Placement, First Know Your Parts
One of the easiest habits to get into for making your placement process more efficient will be to check your component footprints. Many times in my career, I have had to change my placement because of an incorrect footprint, causing schedule delays by forcing significant changes to placement and routing.
A direct solution, though, is having a PCB CAD system that allows you to easily create and change footprints. If your layouts call for modified footprints to service RF, power, or other design technology needs then this tool will save you even more time and frustration. Incorporating a company library to pull parts from and put new parts into will give you a living resource to draw from in the future; however, additional access to external library resources will save even more time that you’d otherwise spend creating new parts in your library system. Managing the organizational constructions of your libraries will make every future design of yours tangibly more efficient.
To place parts, you first need parts to place like these PCB footprints
Liberate Yourself with Placement Constraint Rule Sets
Designs that don’t have placement constraints and rules set up are doomed to eventually have placement violations. CAD tools today come with all kinds of different constraints and rules to combat this. Setting them up correctly will help you to avoid misplacing a component that if left uncorrected will stick out of the top of the device case like a popsicle stick. Here are some of the constraints and rules that you should be working with:
Component clearances: You will want to specify minimum distances that components can be placed from each other both horizontally and vertically.
Component orientation: Most components can be rotated in all directions, but you may need to restrict others to certain rotations. Here is how you ensure rotation compliance.
Board side: If a component such as a specific connector can only be placed on the top of the board, you can set that up in the constraints as well.
Placement rooms: You may have certain areas of the board that can only have specific components it. Examples of this would be areas of sensitive high speed or RF components that need to be isolated from other components. Setting up a placement room on the board will allow you to restrict which components can be placed in this area.
Height restrictions: You may have certain areas of the board that have less vertical clearance than others. These areas need to be set up with a height restriction.
While these are some of the most helpful and most direct component constraints and rules to work with, it’s vital that you get to know your specific design needs. Having the right PCB design software will be able to effectively add and subtract whatever placement constraints your design needs for its success.
There are always new constraints being made with innovations in design needs and technology, stay on top of them.
Component Placement Software Functions and Utilities
Better practices for placement strategies will always help improve your placing efficiency, and there’s a large discussion to be had surrounding them. But there are some CAD functions and utilities outside placement strategies which can help you be more efficient during placement:
Swapping: Make sure to use your swapping functionality as much as you need. You typically will have the ability to swap pins, gates, and even parts which will help your placement efficiency.
Obstacle avoidance: CAD systems usually give you some options to avoid obstacles. These can include the ability to ignore the obstacle, push it aside, or avoid it completely. By picking the best choice for your design, you can help your placement to go faster.
Alignment utilities: These will give you the option to snap your parts to grids or not, or to align your parts to other parts. This can really help to maximize the amount of usable space that you have for parts on your board.
Another function that is very useful to PCB designers is the ability to place and check components in a 3D environment. This will show you on your screen the clearances that you used to only get a report on. Seeing all the obstacles that you have to avoid in 3D can help you to avoid errors and place your components right the first time.
Correct library parts, placement constraints, and utilities & functions will help you to more efficiently place your PCB design. Not only will you get through the placement of your design sooner, it will also help you to design a better circuit board. For the PCB design software functionality built-in, look toward Altium Designer with features such as advanced component placement systems. This will help you to expertly place your components in the most efficient way possible so that you can get started on that routing or other rewards.
Would you like to find out more about how Altium can help you with placement and the rest of the design process for your PCB? Talk to an expert at Altium today.
About the Author
PCB Design Tools for Electronics Design and DFM. Information for EDA Leaders.More Content by Altium Designer