Electronic devices sold in the United States, European Union and other markets are required to comply with various electromagnetic compatibility (EMC) regulations. These regulations exist to protect the
A key aspect of EMC compliance is verifying that your device complies with existing standards for conducted susceptibility.
What is Conducted Susceptibility?
Conducted susceptibility refers to a device’s vulnerability to electromagnetic interference (EMI) transmitted via power or signal lines (conducted emissions).
When a device is susceptible to conducted electromagnetic interference, it may malfunction or stop working when it is exposed to electromagnetic disturbances, such as unintended signals and/or transients.
Devices with a high level of conducted susceptibility are easily affected by EMI from power or signal lines. Devices with a low level of conducted susceptibility are less affected, and can be referred to as having significant conducted immunity.
Conducted Susceptibility and Regulatory Compliance
All major markets for electronic devices, including the United States, Canada, European Union and others, have regulations for electromagnetic compatibility to ensure devices operate safely and effectively in the presence of EMI.
These standards often include specific limits on conducted missions (the EMI a device releases through its cables) and conducted immunity (how resistant the device is to conducted EMI).
In the United States, the Federal Communications Commission (FCC) regulated devices that use the radio frequency (RF) spectrum. In the EU, the EMC Directive mandates that devices comply with conducted susceptibility standards to be granted market access.
How Does Conducted Susceptibility Testing Work?
Conducted susceptibility testing is designed to evaluate how well your device can function when it is exposed to EMI via its power and signal lines. The goal of testing is to simulate a real-world environment where your device might be exposed to conducted emissions while operating.
Test Setup and Equipment
Conducted susceptibility testing involves connecting your device (device under test, or DUT) to specialized test equipment that injects controlled EMI signals into the DUT’s power and signal lines.
Equipment typically used in device conducted susceptibility testing includes signal generators, amplifiers and coupling networks to generate and transmit interference. The DUT is connected to monitoring equipment that records its behavior in response to conducted EMI.
Test Procedures
During testing, EMI signals are injected into the DUT’s power or signal lines at different levels and frequencies. The DUG’s performance is monitored throughout the test to determine if it is capable of continuing operating normally when exposed to conducted emissions.
Key performance indicators, such as voltage levels, signal integrity, and functional outputs, are observed during testing to detect any signs of malfunction or degradation in the device.
The DUT must perform within acceptable limits to pass conducted susceptibility testing. If the device fails testing, modifications to its design such as the use of EMI filters, grounding and/or PCB layout changes may improve its conducted susceptibility for re-testing.
Standards and Test Levels
The specific standards that apply to your device may differ based on its type and your target markets. One of the most common standards for conducted susceptibility is IEC-61000-4-6, which sets limits for industrial, medical and consumer electronics.
This standard specifies the frequency range, test levels and performance criteria that devices must meet to verify they have adequate immunity to conducted EMI.
Importance of Testing in the Design Phase
Like other types of EMC testing, conducted susceptibility testing is typically the most effective when it’s integrated into the early stages of product design as pre-compliance testing.
By identifying potential vulnerabilities to EMI in your device early on, you can make changes to its design to improve its conducted immunity. This proactive approach improves performance in lab testing and reduces your device’s risk of requiring costly late-stage design changes.
Contact Us About EMC Testing & Compliance
Conducted susceptibility is a critical aspect of EMC compliance. Ensuring that your device can operate reliably when it’s exposed to conducted emissions improves its performance and helps you to comply with regulatory requirements in the United States, EU and other markets.
As an ANSI-accredited electronics testing lab and FCC-recognized TCB, we specialize in EMC testing and certification for electronic devices, including conducted susceptibility testing.
To request a free quote for testing and certifying your device, or to ask our engineers a question about the testing and compliance process, contact us online or call us at 866-540-5287.
