8 PCB Layout Tips

 Let’s face it; the fun part of a PCB design is never in placing the hundreds of components. The excitement starts when you start routing the nets together. For some PCB designers, PCB routing is an art, while others strive to make it an opportunity to display their technical prowess. Here are eight PCB layout tips to ensure your design success – from preparing your schematic to providing all documents to the manufacturer.

PCB Layout Tips and Tricks 

Let’s take a deeper dive into the eight tips above. 

1) Have Your Schematic Ready

It is not unusual for those doing PCB layout to gloss over the importance of preliminary steps before placing and routing components. It’s easy to dismiss attention to detail in the schematic and other prep work because you expect them to be taken care of later.

Because of this thinking, design checks aren’t run, parts aren’t validated, and basic drafting tasks like cleaning up text to make it more readable aren’t followed. You may find out that those missed design checks would have caught some nets that were incorrectly connected. Your layout has traces that need to be ripped up, or at worst, parts have to be completely replaced to accommodate the corrections. So, do yourself a favor and ensure the complete schematic is ready before you begin the layout.

2) Verify Data Before You Start the Layout

Jump-starting a PCB layout before having all the board data at hand usually causes more problems than it’s worth. You may find yourself in a position where you have to rip up and modify portions of your design to accommodate a change that should have been done before you started your work. Here are a few items that you should verify first:

• Board Layer Stackup: Make sure the board layer stackup has been finalized before you start. Adding or deleting board layers can be painful, sometimes resulting in redoing the entire layout.

• Board Dimensions: Moving carefully placed components because your board outline needs a cut-out that you didn’t know about can cost you a lot of time. Check first to save yourself a lot of trouble later on.

• Keep-out Zones: These zones could be for several reasons, including mechanical, thermal, height, or sensitive circuitry. If you don’t understand these requirements before you start layout, there’s a good chance you will have to make unexpected changes later.

Check first before you start, and you will hopefully save yourself a lot of grief later. And do yourself a favor by leaving some extra room in your placement for modifications, if possible. 

3) Group Components By Function

Now, you are ready to place components. But take care. Improper component placement can lead to a horde of issues that affect the PCB's functionality, durability, manufacturability, and serviceability. For example, if you’re designing a PCB that requires scheduled maintenance, placing connectors at the wrong location can make servicing a pain for the field technicians.

You should ensure the components are segregated according to their functional block in the circuit. For example, power management components shouldn’t be jumbled with analog parts, and high-speed digital communication should be kept on its own. The rule of thumb is to keep the noisiest signals away from the highly sensitive ones. Also, grouping components according to their function gives you better control of their return path. 

4) Keep Components Away From Heat Dissipating Areas

In power-demanding applications, the voltage regulator heats up significantly. Chances are, you’ve included some heat-dissipating vias to increase the heat dissipation rate. However, it is still unwise to place other components near the regulator. The same applies when using a power op-amp or other heat-emitting device.  

5) Place Board-To-Wire Connectors Near The Edge

System installers and technicians will appreciate it if you keep board-to-wire connectors near the edge of the board, especially if the wire needs to be screwed on. Not only does it look organized, but keeping connectors near the edge prevents unwanted contact with other components on the PCB.

6) Standardize the Component Placement

All ICs, regardless of their footprint, have a pin 1 marker. If you don’t want your assembler to grumble each time you submit a design, ensure they are all aligned in the same direction. This increases the efficiency of the assembly process and reduces placement mistakes.

Standardized pin 1 orientation on components.

7) Make Space For Copper Traces

Electronics are demanding for smaller PCBs, but sometimes there is an optimal size you need to stick with, or else you’ll find it impossible to complete routing all the traces. When placing components, ensure sufficient gaps for copper traces to pass through, especially near components with hundreds of pins.

8) Don’t Neglect the Final Manufacturing Output Files

Managing supply chain information and component sourcing, generating assembly drawings and Gerber files, and compiling board information in standardized file formats are simple but pivotal features of the production process. Don’t forget that your PCB manufacturer or fabricator is just an email or phone call away. Including their voice in your design process can save headaches as you try to meet their specifications at the end of a long design process.

Remember that you are building a circuit board, which will only be as successful as the manufacturing documentation you create. So give yourself plenty of time, don’t rush the process, double-check all of your work, and make sure that you send out a full and complete documentation package.

Cadence Provides the PCB Layout Tools You Need

These PCB layout tips should give you a good starting place. You can also help yourself by using PCB design tools that are built to help designers like you get the job done as quickly and efficiently as possible. OrCAD PCB Designer is a powerful set of design tools that allows you to lay out your PCB design quickly and accurately.