Complying with EMC Standards for Automotive Electronics
By ZM Peterson • Jun 15, 2020Any electronic product that is to be sold at high scale in the US, Europe, Japan, and other industrialized countries will have to comply with multiple standards. These standards cover nearly all aspects of performance, manufacturing, materials, and disposal. EMC standards are some of the most important, yet they remain the domain of specialists.
Although EMC standards can seem esoteric, they are critical for any product that must operate near other electronics that emit spurious electromagnetic radiation. In an automobile, there are high currents being drawn into a number of systems that also through off strong radiation, which can then be received by other systems within the vehicle. Although designers execute a meticulous dance between system placement and cable routing between different components, designers still need to create PCBs that can comply with EMC standards for automotive systems. If you’re designing new products for a new automobile, here’s what you need to know about your next design.
EMC Standards for the Automotive Industry
There is no "single" set of standards on new vehicles. Different countries have different regulations, and the industry as a whole has come together to develop a broad range of other standards on electronics and mechanical systems in vehicles. On the electronics design side, there are few organizations that specify EMC standards for automotive electronic systems. Including specifications from every standard that governs the industry takes its own website (multiple in fact), but we can point to two relevant standards organizations that you should consider when designing your new product.
CISPR (International Special Committee for Radio Protection)
CISPR provides standards beyond the automotive industry, all of which deal with radio disturbances sensed by electronics. These standards define acceptable limits on emission and reception of radiated EMI. In terms of EMC standards for automotive electronics, the CISPR standards are intended to protect sensitive RF circuitry from other components within a vehicle or outside a vehicle.
ISO (International Organization for Standardization)
While the CISPR standards cover design aspects that are intended to suppress EMI, the ISO standards are designed for testing. Note that CISPR does not specify how you design the product to suppress emitted or received EMI, it simply specifies what the limits on radiated/received power should be. The ISO tests are highly specific, both for vehicles and other products. These tests focus on evaluating immunity to various sources of interference that may be encountered while driving.
Most EMC simulations focus on near-field radiation around an ECU or other strong emitter in a vehicle. This helps designers spot a potential EMC problem before prototyping.
Other Automotive EMC Standards
The SAE (Society of Automotive Engineers) J1113 family of standards cover various electromagnetic compatibility measurement procedures as well as specifications for immunity to radiated interference. SAE is the premier standards organization for automobiles, but they primary deal with mechanical standards, not electrical standards. Still, these standards should be considered in terms of design for low EMC.
The final relevant standards organization is IPC (Association Connecting Electronics Industries), although there are no automotive-specific EMC standards at this time. However, some IPC standards, such as IPC-9592, cover telecom and information technology equipment, which includes specifications on EMC standards. As more automobiles become connected to the broader world over V2X networks, these standards might become mirrored on automobiles.
Designers should continue to pay attention to automotive Ethernet standards, especially as commercially-available infotainment and ECU systems top 1 Gbps data rates. This will be compounded by the fact that more sensors will be used in automobiles to support ADAS systems. 24 and 77 GHz radar systems are already preferred to lidar (unless you believe Elon Musk), but they also can create problems with emission and reception of unwanted radiation within a vehicle and between systems. Designers will need to pay attention to high speed and high frequency board design guidelines to ensure their systems comply with the industry’s EMC specifications.
At NWES, we pay attention to EMC standards for automotive systems and other important areas, such as defense and aerospace. If you need a design firm to help you create new products for regulated industries, NWES is here to help your company design modern PCBs and create cutting-edge technology. We've also partnered directly with EDA companies and advanced PCB manufacturers, and we'll make sure your next layout is fully manufacturable at scale. Contact NWES for a consultation.
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