PCB design is both an art and a science. There’s a ton of technical know-how and measurements to consider when dealing with trace widths, layer stackups, schematics, etc. But then you get to the artistic side of PCB design with component placement, and this is where things get interesting.The artistic design can make your pcb unique. Your pcb assemblymanufacturer is producing pcbs based on your design, so the beautiful design will make your pcb look good.
The truth is, there is no “right” way to place components, and this freedom is ultimately what makes the PCB layout process so dang fulfilling and creative. It’s all up to you and what you want to design. That’s not to say that you can do whatever you want. There’s still the humbling reality that the digital design you create needs to be manufacturable in its physical form, which is why you’ll want to follow the 10 tips below to make the most of your component placement flow.
What’s So Important About Component Placement?
There’s a common saying that goes something like this – PCB design is 90% placement and 10% routing. This is entirely accurate. Taking the time to precisely place your components will make your life a whole lot easier when it comes time to route everything, while also giving your board its best electrical performance. But what happen if you just slap your components down without care?
· Hours Wasted. You’ll likely create a nightmare for yourself when you find out that some of your parts don’t even have enough space to be routed because you packed them too close together. The worst component placement jobs can lead to an entire board that needs to be started again from scratch.
· Busted Boards. Let’s say you do manage to place down some components and traces and ship your files off to your manufacturer. Next thing you know you might get a board back, that doesn’t work because your parts weren’t soldered correctly (more on this later).
· Ugly Aesthetics. Let’s face it, as engineers we love symmetry and precision, and there’s nothing more unsettling than seeing a board that wasn’t given some proper love and care during its component placement. It’s just plain lazy.
Make sense? Here’s the real kicker – there’s no universally “right” way to do it. Give a schematic to 100 different engineers, and you’ll likely get 100 different layouts back. This is why the PCB layout process is viewed as an artistic process.
Not a fan of all the vague ideas of “right” and “wrong”? Here’s a hint to see if you’re on track with your component placement. After throwing down all of your parts, crank on the autorouter in Autodesk EAGLE. If you don’t get at least an 85% completion rating, then this is a good sign you need to spend some more time on your component placement.
Now that we’ve got the Why out of the way let’s move on to some practical tips you can use in your first design project!
Tip #1 – Understand Your Mechanical Constraints
Before you ever place a part down, you’ll want to know exactly where your mounting holes and edge connectors go and what kind of mechanical enclosure to fit your board.
Why?
Understanding these variables will affect both the size and shape of your board. We’ve seen many engineers design a board that doesn’t fit its enclosure, only to spend hours reworking their entire design again.
You can do yourself a favor by plugging in clearance requirements for your mounting holes in your design rules before beginning a component placement process. This will let you focus on the creative stuff while not worrying about your mechanical constraints.
