PCB Design Guide – PCB Layout
We’ll cover steps 6 – 9 on this page of the pcb design guide. These 4 steps together make up the entire subject of pcb layout.
There are a few topics that need to be discussed before proceeding with pcb layout.
Board Setup and PCB Design Rules
Step 6 of the pcb design guide is getting the board setup and ready for placement. There are several board setup options and pcb design rules to consider when designing a pcb.
Multi-Layer Board Design
At this stage in the game you’ve probably got an idea of what shape your board, but you might not have considered the inside of the board yet. A pcb is composed of layers, each facilitating routing of signals or power. Depending on your design you may need several layers to even make your board routable, however simple designs can be completed on a single or double layer printed circuit board.
Understanding PCB Layers
Ground / Power Planes
Board and Layer Thickness
If you have any high current circuits like power supplies, motor drivers, or high-power LEDs you’ll need to consider the copper thickness needed to keep the current from burning up the traces. You’ll also need to consider the FR4 thickness and how thick the overall stackup will be after production.
Choose PCB Board Copper Thickness
Overall Circuit Board Thickness
PCB Design Rules
There are many options and design rules that may be setup to assist you during the placement and routing phase of your design. Rules such as minimum trace width and clearance between traces are two of the most common. During placement or routing if you violate a design rule you’ll generally receive a warning so the issue can be corrected.
It should be mentioned that design rules are heavily influenced by manufacturers capabilities. You should check with your manufacturer’s capabilities to ensure your board is producible.
Component placement is thought to be the single most important aspect of pcb design in general. With good placement the routing becomes extremely easy. However there is no single way to place components. Here are a few general guidlines to assist in placing components effectively.
Traces that should be manually routed are clocks and transmission lines. These traces generally need to be shorter and have routing priority over other traces.
The autorouter will save you hours of time. Learn this tool well.