EMC Standards 101: A Comprehensive Guide for EMS and OEM Companies

Every revolutionary electronic product, from the smallest wearable to the most complex industrial equipment, shares one critical milestone on its journey to market: electromagnetic compatibility (EMC) certification. Yet, this crucial step remains one of the most challenging hurdles in product development, with our research showing that 70% of new products fail their first EMC compliance test.

If a new electronic product will ever make it to market at massive scale, it will need to comply with certain regulatory standards. There are several to consider, such as environmental regulations like REACH and RoHS, as well as compliance requirements relating to user safety. Among all the requirements placed on electronics and PCBs, there is one set of regulatory standards which remains difficult for many design teams: EMC standards.

The EMC standards used in the electronics industry correspond to real regulations relating to the performance of electronic products, and these regulations vary by product type and region. Furthermore, regulations can have some overlap in certain products, so it is important to know which standards will be used to evaluate your design. While we can’t give a complete overview of every standard, we can offer guidance on how EMC standards will impact your product’s path to market.

Understanding EMC: The Foundation of Modern Electronics

Imagine placing your new smartphone next to an old radio. If you hear interference through the radio's speakers, you're witnessing an EMC issue firsthand. Electromagnetic Compatibility (EMC) isn't just about preventing interference – it's about ensuring your product can coexist harmoniously with other electronic devices in its intended environment.

Think of EMC as having two essential aspects:

1. Your device must not emit excessive electromagnetic energy that could disrupt other equipment
2. Your device must continue functioning correctly when exposed to electromagnetic interference from other sources

What Is the Meaning of EMC?

EMC stands for “electromagnetic compatibility,” and it refers to an electronic product’s ability to function successfully in an electromagnetic environment that resembles the product’s real-world operating conditions. To achieve electromagnetic compatibility, electronic circuits and assemblies must limit the amount of electromagnetic radiation that they emit and resist the negative effects of received electromagnetic radiation.   

EMC Standards Compliance Remains a Challenge

EMC standards assess products across four critical areas:

1. Radiated Emissions

Like a lighthouse beacon, every electronic device emits electromagnetic energy. EMC standards set strict limits on these emissions, ensuring they won't interfere with nearby equipment. Imagine your product as a neighbor in a crowded apartment building – it needs to keep its "noise" down to maintain harmony.

2. Conducted Emissions

Electronic noise doesn't just travel through the air; it can also flow through power lines and connecting cables. Standards regulate these conducted emissions to prevent your device from sending unwanted signals through shared electrical systems.

3. Electromagnetic Susceptibility

Your product must demonstrate resilience against electromagnetic interference, much like a well-built house withstanding various weather conditions. Can your device maintain normal operation when exposed to the electromagnetic "weather" of its intended environment?

4. ESD and Surge Protection

Static electricity and power surges are inevitable challenges in the real world. Your product needs to handle these events gracefully, much like how a surge protector guards your home electronics.

A study done by the DENPAFLUX engineering and research team found that approximately 70% of new products will fail EMC standards compliance in at least one of these areas. The result is the need for a redesign of the PCB or the product, followed by another round of compliance tests. EMC testing is not cheap and must be performed at a laboratory that is certified to test against the relevant EMC standards. 

There is also some confusion from new designers as to what EMC standards are intended to assess and specify.

What Is an EMC Standard?

All EMC standards are performance and testing standards. They define the radiated and conducted emissions criteria and susceptibility criteria that a system must meet in order to be considered compliant, as well as the testing procedures needed to verify compliance.

EMC standards are not PCB design or system design standards. Unlike other industry standards such as IPC, they do not tell you how to design a system to reach emissions and susceptibility performance requirements.

It is the product designer’s responsibility to determine which EMC standards are likely to apply to their product, along with the required PCB design practices that can help ensure compliance. In addition, the designer should have a clear definition of the product’s classification and capabilities, as this will determine the testing requirements for the product.

EMC Standards and Product Classification

To determine which standards are applicable for your product, ask yourself some preliminary questions:

• Where will the product be sold (USA, Europe, China, etc.)?
• How would the product be classified (commercial, industrial, etc.)?
• Is the product an intentional or unintentional radiator?

The answers to these two questions will dictate which standards govern your product and the testing requirements. The main regulatory bodies and standards commissions that develop EMC standards are listed below.

• US Federal Communications Commission
• European Standards (a.k.a., European Norms, or EN)
• Comité International Spécial des Perturbations Radioélectriques (CISPR, a committee of the IEC)

Although these three governing bodies have the broadest EMC standards coverage, other countries have developed their own EMC standards. For example, national EMC standards are in place in Australia, New Zealand, Taiwan, China, Japan, and Canada.

Specific standards have been developed for broad classes of products, ranging from wearable electronics to landscaping equipment. Common EMC standards, the associated governing body, and a description of the covered products are given below.

These are just a subset of the range of standards used in the electronics industry to define EMC performance and testing requirements. In the defense and aerospace industries, there are more stringent EMC standards, namely the Radio Technical Commission for Aeronautics (RTCA) DO standards and MIL-PRF standards.

To get more information about any of these standards, contact a certified testing lab or the relevant regulatory body directly. Overviews of EMC standards are also available online and can help provide some insight into the EMC certification process.

Module Certification

Some products, such as microcontrollers and Bluetooth transceivers, are available as modules that have already passed EMC testing. There is a perception that modules in general will ease the path toward EMC compliance, but it’s difficult to know how much they will really help. First of all, not all modules are certified. If there is no publicly available documentation or clearly visible marking indicating compliance, then one should assume that a module has not passed EMC testing. Modules that have passed EMC testing and have a module certification will contain relevant markings on the product, such as the CE and FCC markings on the ESP-WROOM-32 module shown below.

ESP-WROOM-32 module on a baseboard. The CE and FCC markings indicate module compliance.

Furthermore, even pre-certified modules will not guarantee EMC compliance for a new product. These modules do not eliminate the need for PCB design practices that are known to reduce EMI. The baseboard for the module can be a source of EMI even in the case of a very-low-noise module. This is why designers should focus on simulating and validating a PCB design for a new product before spinning prototypes for testing, even when a module is being used as the main component in the design.

Taking Action

The journey to EMC compliance is like building a strong foundation for a house – each step builds upon the previous one to create a robust structure. Let's explore how to transform your EMC challenges into opportunities for product excellence.

Here's what you can do today:

1. Review your product's target markets and applicable standards
2. Implement EMC considerations in your design process
3. Plan for pre-compliance testing
4. Consider partnering with EMC experts for guidance
5. Partner with DENPAFLUX who provides 360 services when it comes EMC challenges.

Designers may not realize that the phrases “electrically functional” and “compliant with EMC regulations” do not have the same meaning. A prototype for a new device can be perfectly functional in all aspects and still fail EMC testing, in which case the design must be modified to solve the problem in some way.

Locating an EMI source in a PCB and performing pre-compliance checks before formal certification testing can be a tall order for many designers. EMC compliance is a cornerstone of successful product launches for EMS and OEM companies. By understanding regional standards, embedding EMC best practices early, and partnering with industry experts like DENPAFLUX, your company can save costs, avoid delays, and build reliable products that meet global standards.

With DENPAFLUX by your side, EMC compliance becomes less of a hurdle and more of a competitive advantage.