PCB Signal Integrity


When designing an ordinary PCB, usually that which does not involve high speed signals, PCB signal integrity is not a major concern. As the PCB design advances to multilayer PCB and also involves high speed signals, PCB signal integrity becomes an important thing to consider. For the PCB Prototype to perform its job as expected, the PCB designer must put into practice measures that will ensure that the PCB Produced has the required signal integrity to perform its operation. A PCB trace can be used to carry a high current, a changing current or a sensitive analog or digital signal. In all of these cases, the design must be done to ensure that PCB signal integrity is maintained.


Among the unwanted capacitance and inductance in the PCB, another great signal distractor is crosstalks. When a PCB trace is carrying current, some electromagnetic induction happens around this conductor. Crosstalks happens if this electromagnetic induction is unwanted and it radiates to the surrounding traces. This greatly compromises the PCB signal integrity. Another factor that could affect the PCB signal integrity is the PCB length and the number of Vias in the PCB.

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There are some design measures that could be taken to improve PCB signal integrity. One of the ways is to ensure that you use the shortest possible PCB trace when routing. Also, when designing your PCB, use as few vias as possible. These two simple rules will minimize unwanted signal induction and hence improved PCB signal integrity. It might be tricky to completely eliminate crosstalks during PCB design. However, if your PCB signal integrity is a major consideration, every effort should be made right from design stage! Since every signal in a PCB has a return, there is always a loop area. One of the simplest ways to deal with crosstalks is to minimize this loop area since electromagnetic radiations are directly related to the loop area. It is also a good practice to ensure that you use the smallest PCB thickness as possible. Proper signal trace termination is another tactic that will cut out some crosstalks and improve PCB signal integrity.