How To Design a Simple Layout for a Circuit Board

A circuit board connects electronic components by using a conductive pathway that is etched on a copper sheet that is laminated onto a non-conductive substrate. Before you can begin to lay out your PCB board, you should have an accurate schematic or circuit diagram ready. It wouldn't do to go straight into making the PCB board with only a circuit in your head or a draft of a schematic drawn on loose sheets that have no order.

Your PCB design is an assembled version of your circuit diagram. When your circuit diagram is logical, neatly prepared and clearly laid-out, it will be easier to prepare the PCB design. It would be good to place small notes on the circuit diagram that give short reminders for laying out the board or to explain the diagram to those reviewing the design.

Those who know how to make circuit boards would say that making them is 90% placement and 10% routing. Where you place components is the most important portion of laying out a board. When you have good component placement, your job of laying out the circuit board will be easier and the electronic performance will be great. If you happen to have bad component placement, your routing job will have problems and the electronic performance will be dismal.

There is no uniform or standard way of placing components in a board. But there are simple, basic rules to follow that will simplify complex designs and give good electrical performance. Here are some basic steps for laying out a simple, yet complete board.

1. The first thing you need to do before anything else is set your snap grid and your visible grid and assign the default track/pad sizes. You need to set this to make sure you don't run out of routing space or have too much space that your large board does not use efficiently.
2. Put down all components on the board next. If you are using a PCB program, select each component you will use from the library and manually lay them down. Now you can see if your board is small or large.
3. Analyze the design. Divide and assign your components into "building blocks" where it is possible.
4. Separate particular blocks that require electrically sensitive handling and assign them to a bigger block.
5. Take each building block separately. Route each one outside the board.
6. Position the completed building blocks on the board. Generally, components are neatly lined up. But don't push for aesthetically pleasing if it results in an electrically poor layout.
7. Route the connections between building blocks, including power connections. A design rule check (DRC) can be run to check for connectivity problems between blocks and for correct widths and clearances.
8. Ask someone to check your layout. You might have overlooked something and a fresher pair of eyes might see problems where you didn't think there would be.

Print out your circuit board design when you are finished and study it by connection. You can now be confident that your design is electrically correct after you have assessed each part.