Electromagnetic Compatibility (EMC) and Electromagnetic Interference (EMI) are crucial design considerations when designing Printed Circuit Boards (PCBs). EMC ensures that your device functions without interference from other devices in its shared operating environment, while EMI is electromagnetic energy that affects the functioning of the device. Both these properties must be taken into account when designing PCBs, as they can affect the performance of electrical devices if not properly designed. So, what are the tips and techniques to be implemented while designing PCBs to mitigate the effects of EMI/EMC? This post lists a few PCB design guidelines with the help of which the effects can be avoided or minimized.
Best Practices in PCB Design: Techniques for EMC Compliance and Reduced EMI
There are a number of design strategies that can be applied when creating PCBs that adhere to EMC and EMI requirements. These involve setting up ground planes, placing vias correctly, and offering suitable return paths. The following design strategies can also help to mitigate the effects of EMC and EMI.
- Stack Up: In order to minimize the risk of EMC and EMI, it is highly recommended to design PCB stack up sensibly. Consider the thickness and dielectric constant of each layer, along with the placement of your power and ground planes. Grounds between signal layers provide shielding and reduce unintentional radiation from signal lines, making it easier to maintain return paths on transitions. This helps minimize crosstalk and interference among different signals.
- Proper Partitioning: Manufacturers can reduce the risk of electromagnetic interference and electromagnetic compatibility by partitioning the board. A common approach to achieving this is to physically separate analog and digital tracks. Depending on the PCB design, there are multiple ways to partition the board and all methods contribute to improved signal integrity and compliance with industry regulations.
- Signal Routing: Another most effective way to avoid EMC and EMI involves routing the signal on the circuit board. This can be done in a number of ways, but the most common is to route signals from the exterior to the inside layers. Being said this, it is highly advisable to keep the signals apart to prevent cross-talk between traces.
- Trace Spacing: Circuit boards must be very carefully designed to maintain the proper spacing of traces because this plays a major role in electromagnetic emission control. For optimal performance and safety, the following measures should be taken to ensure correct trace spacing:
- Route differential traces closely
- Use Vias like a pro
- Use guard and shunt traces for clock lines
Although these design considerations will help reduce EMI and improve EMC of the boards, they are not enough. The boards are still susceptible to EMI. This is where various PCB shielding solutions will help.
A Brief Overview of Various EMI Shielding Solutions
As the demand for miniaturization and higher data rates in electronic devices continues to grow, so does the need for effective electromagnetic interference EMI/EMC shielding solutions. One of the most effective ways to reduce or avoid EMI/EMC is by using Board Level EMI shielding. EMI shielding is a process of enclosing electronic components and circuit boards in a conductive material that inhibits the passage of electromagnetic waves. This is usually done by shielding the device in a conductive casing/PCB shielding metal cans or by using PCB shielding frames and covers. All these shielding solutions have certain downsides and board-level EMI shields stand out in this context. These shields are designed in one-piece or multi-piece designs. Unlike metal cans, frames, or covers, these shields do not add to the weight of the PCB and can be easily removed when repairs are required.
If you have been considering these board-level shields for your PCBs, it is important to partner with a qualified provider like XGR Technologies. Their SnapShot® EMI shields offer a unique and superior alternative to traditional PCB shields as they are innovatively designed to provide superior protection against all types of electromagnetic interference. Introduced in 2002, these shields have been successfully used employed in various GPS devices, military radios, medical imaging equipment and network computers. These shields have helped electronic manufacturers to achieve EMC, minimize EMI/RFI, and comply with government regulations. The experts at XGR Technologies can customize these shields to meet your application requirements. Get in touch with the experts at the company to discuss your requirements.