Tips to Overcome EMI Problems in PCB Designs

The complexity of electronic systems has led to a tremendous increase in the frequency of electronic signals and processors in electronic devices. Greater speed and density lead to an increase in radioactivity, while low pressure and high sensitivity lessen the system immunity.

Electromagnetic interferences are categorized as radiation interferences and conduction interferences. Radioactive interferences result when the source uses space as a medium to interfere with the electrical networks and signals. On the other hand, conduction interferences arise when electrical network interferes with the signals by way of a conducting medium.

However, electromagnetic interferences pose threat to the safety and reliability of various electrical components and devices. So as to avoid such obstructions, PCB design is the best solution. These interferences can be overcome with the help of EMI shielding, EMI suppression coating or EMI simulation design.

Here are some tips to overcome common EMI problems in PCB designs. Have a look at them.

  • Power Bus:

The limited frequency of response of capacitors makes it difficult for the capacitors to generate optimal levels of power needed to run the circuit in PCB designs and are the main causes for voltage drops.

Hence, to solve this problem, the power pins ought to be as short as possible. This will provide for the high frequency of energy for clean outputs and lessen the effect of EMIs. The devices that are prone to frequent changes in the current rates should be covered with an extra layer of high dielectric constant materials.

  • Electromagnetic Shielding:

EMI shielding is an effective way to mitigate the immense effects of electromagnetic interferences. This is also known as a layering strategy that involves the placement of signals either on the same PCB design or close to the power or ground plane.

From both signal routing and power supply point of view, stratification strategy that is adjacent to power and ground plane is considered best.

  • Multi-Power Layer Design:

The inappropriate layout of PCB design leads to cross interferences between the network signals. In order to avoid such interferences, the design layout of PCBs should be divided into power planes and ground planes.

In case an insulating layer is not placed between adjacent power planes, a minute change in voltage levels will affect the electromagnetic interferences drastically. Further, if there are varied voltage requirements for multiple circuits on the board, then power sources for both power and ground planes should be made.

Moreover, the signal traces should be kept short and the corner layout of 135 degrees should be preferred. Also, demarcations between analogue and digital signals must be made before connecting them to the power ground.

  • Differential Component Distribution:

Circuit and anti-circuit interference capabilities are adversely affected by differential component distribution. Hence the blocking of signals should be made depending on the strength and functions of analog and digital signals.

Further, this allows for a reduction in levels of radiations, resulting in improvement of the anti-jamming capacity of the circuitry of PCB designs.

 

Leave a Reply