22-02-2018

Every PCB is different; varying in form factor, functionality and complexity. Designing it is like puzzling, but with rules that the design must follow. Copper patterns on the PCB represent the electrical connections necessary to ensure the functionality of a product. Copper patterns are not always logical in the sense of: We take the shortest route from point A to point B. In fact, in some cases it even seems illogical. The question then is why?

This phenomenon has to do with guaranteeing the signal quality between the component connections themselves (also called “Signal Integrity”), which is often specified by the relevant component manufacturer. For example, some connections need to be exactly the same length (and run side by side), which can result in a wavy copper pattern on the PCB (differential pair). Think, for example, of USB2/3 connections or DDR3 connectivity (which every PC has nowadays).

In addition to the length of the connections, design criteria such as impedance (e.g. Ethernet, USB, RS485, NFC, GSM, WiFi), isolation distances (intrinsically safe) and EMC can also have a major influence on the copper pattern of the PCB.