What are PCB Design Rules

In the process of PCB design ,engineers should consider a lot . They strive to follow design rules and reduce production hassles. Summarize the common rules in the PCB design process, hoping to bring some help to everyone’s design work .

Why should we know the PCB design rules

PCB design depends on a set of rules，These rules cover everything from the components to the specific circuit line. In order to reduce the chances of manufacturing errors , to lower the cost ,the pcb can work smoothly, designers need to design strictly according to the rules.

The successful pcb design depends on 90% layout and 10% routing, let’s take two parts about PCB design rules.

1.PCB Layout Rules to Follow in Your Design

1.plan your stack-up

2.Draw the board outline.

3.Component placement

4. install electronic components within 1.27mm aroundmounting holes, such as tool holes and standard holes.

Do not mount components within 3.5mm (for M2.5) and 4mm (for M3) around the mounting holes such as screws;

5.Avoid placing holes under the components such as the horizontally mounted resistors, inductors (insers), electrolytic capacitors, etc., so as to avoid short-circuiting the vias and component housings after wave soldering;

6.The distance between the outer side of the component and the edge of the pcb board is 5mm

7. The outer side of the mounting component pad and the outer side of the adjacent interposing component are greater than 2 mm

2.PCB Routing Rules to Follow in Your Design

Even though we stated earlier that the placement drives the routing, it is also true that the routing has an impact on how the parts should be placed. For this reason, components also need to be placed with routing considerations in mind. Here are some of those routing rules of thumb:

Give yourself enough room for routing large data memory buses. Remember to allow for escape routing as well.
Place parts so that sensitive digital signals do not get routed through analog circuitry or analog signals through digital circuitry.
Make sure that there is enough room for sensitive signals such as differential pairs, which will need extra spacing to other routing.
Do not let your component placement force you to route traces across voids or splits in the reference ground plane. This will ruin the signal return paths and create noise on the board.

Measured trace lengths
Matching trace lengths
Trace routing topologies
Differential pair trace routing
Layer rules, unique spacing, and specific widths for controlled impedance routing
Power net rules for wider widths and clearances
High-speed signal paths
Trace timing or tuning

This gives you the freedom to consider all possible scenarios in your design without having to worry whether or not your efforts are in violation of design rules.