In the highly complex electronic/electrical (E/E) architecture of modern vehicles, countless electronic control units (ECUs) require real-time, reliable data exchange to enable functions ranging from powertrain control to advanced driver assistance systems (ADAS). Serving as the physical layer foundation for all this, the CAN Transceiver PCB plays an indispensable role. It is not only a bridge connecting the digital logic world with physical bus signals but also a critical cornerstone ensuring the stability, security, and reliability of the entire vehicle communication network. Any oversight in this aspect could lead to communication interruptions, functional failures, or even severe safety incidents.

As an IATF 16949-certified professional automotive-grade PCB manufacturer, Highleap PCB Factory (HILPCB) fully understands the extreme safety and quality demands of automotive electronics. We don’t just provide circuit boards; we deliver system-level solutions compliant with ISO 26262 functional safety standards and rigorously tested under AEC-Q certification. From the perspective of automotive electronics safety experts, this article will delve into the core challenges faced by CAN Transceiver PCBs in design, manufacturing, and testing, while showcasing how HILPCB’s exceptional manufacturing and assembly capabilities safeguard your automotive projects.

Core Functions and Challenges of CAN Transceiver PCBs in Automotive Electronics

The CAN (Controller Area Network) transceiver serves as the physical layer interface for the CAN communication protocol. Its core function is to convert TTL/CMOS logic levels output by ECU microcontrollers into the differential signals (CAN_H and CAN_L) required by the CAN bus, and vice versa. This conversion process must be executed flawlessly in the high-speed, high-interference automotive environment. Consequently, the CAN Transceiver PCB, which carries the transceiver and its auxiliary circuits, faces multiple challenges:

1. Harsh Operating Environment: The internal temperature of a vehicle can fluctuate dramatically from -40°C to 125°C, accompanied by continuous mechanical vibrations and shocks. This demands that the PCB exhibit exceptional heat resistance, vibration resistance, and long-term reliability, especially in high-stress EV PCB applications.
2. Complex Electromagnetic Interference (EMI): Engine ignition, motor drives, radios, and other equipment generate intense electromagnetic radiation, posing threats to CAN bus signals. PCB designs must demonstrate outstanding EMC (electromagnetic compatibility) performance to suppress interference and prevent becoming interference sources themselves.
3. Stringent Functional Safety Requirements: In safety-critical systems like ADAS, braking, and steering, any interruption in CAN communication could lead to catastrophic consequences. Therefore, the design and manufacturing of CAN Transceiver PCBs must strictly adhere to ISO 26262 standards, ensuring the system enters a safe state in the event of a failure.
4. High Reliability and Longevity: Automotive designs typically target a lifespan exceeding 15 years or 300,000 kilometers. The PCB and its solder joints must withstand thousands of thermal cycles and continuous mechanical stress without delamination, cracking, or connection failures. This is particularly critical for Platooning PCBs supporting future autonomous driving.

ISO 26262 Functional Safety Requirements for CAN Transceiver PCB Design

ISO 26262 is the "gold standard" for functional safety in the automotive industry. For CAN Transceiver PCBs, compliance means embedding "safety" into the design from the outset. Depending on the Automotive Safety Integrity Level (ASIL) of the connected ECU, design requirements vary.

• ASIL B/C/D Applications: In these high-safety-level applications, potential failure modes of CAN transceivers-such as bus dominant/recessive clamping or driver shorts-must be considered. PCB designs need to incorporate corresponding safety mechanisms, such as:

  • Redundancy Design: Employing dual CAN transceivers or redundant communication paths to ensure backup paths can take over if the primary path fails.

• Diagnosis and Monitoring: Integrating voltage monitoring, temperature sensing, and bus status detection circuits on the PCB enables the ECU to diagnose transceiver health in real time.

• Fault Isolation: Through meticulous circuit design, ensure that a single transceiver failure does not affect the normal operation of the entire CAN network.

• Hardware Reliability Metrics: ISO 26262 requires quantitative analysis of random hardware failures, including Single Point Fault Metric (SPFM), Latent Fault Metric (LFM), and Probabilistic Metric for Hardware Failures (PMHF). HILPCB helps customers fundamentally reduce hardware failure rates by providing high-quality, high-reliability PCBs, making it easier to meet these stringent metric requirements.

Withstanding Harsh Environments: AEC-Q100/200 and Environmental Testing Standards

The AEC-Q series standards established by the Automotive Electronics Council (AEC) serve as the entry threshold for components and PCBs to enter the automotive field. AEC-Q100 applies to integrated circuits (such as CAN transceiver chips), while AEC-Q200 targets passive components. Although there is no dedicated AEC-Q standard for PCBs, the industry generally requires that PCB manufacturing and materials must support the components mounted on them to pass these rigorous tests.

HILPCB's automotive-grade PCBs are designed and material-selected with these requirements in mind:

• High-Temperature Resistant Materials: We prioritize substrates with high glass transition temperatures (Tg) (e.g., Tg170°C, Tg180°C) to ensure PCBs do not soften or deform in high-temperature areas like engine compartments, maintaining structural stability. For applications with special heat resistance needs, we offer professional High-Tg PCB solutions.
• CAF Resistance: Conductive Anodic Filament (CAF) is a major failure mode for PCBs in high-temperature and high-humidity environments. By selecting substrates with excellent CAF resistance, optimizing drilling processes, and strictly controlling resin filling within the board, we effectively prevent micro-shorts, which is particularly critical for high-stress EV Power Module PCBs.
• Thermal Cycling Reliability: Automotive PCBs must withstand thousands of temperature cycles from -40°C to 125°C. We use materials with low coefficients of thermal expansion (CTE) and optimize copper plating processes to ensure long-term via reliability, preventing cracks caused by thermal stress.

Electromagnetic Compatibility (EMC): The Key Barrier to CAN Bus Stability

EMC is the top priority in CAN Transceiver PCB design. Excellent EMC design ensures stable communication for CAN networks in complex electromagnetic environments while avoiding interference with other in-vehicle electronic devices (e.g., radios).

HILPCB's DFM (Design for Manufacturability) review team works closely with clients to optimize EMC performance from the PCB layout and routing stage:

• Strict Control of Differential Pairs: CAN_H and CAN_L signal lines must maintain strict equal length, spacing, and parallel routing to maximize common-mode rejection ratio. Using advanced EDA tools and manufacturing processes, we ensure impedance control accuracy within ±5%.
• Rational Layer Stackup and Grounding: In multilayer board designs, we recommend using a solid ground plane to provide the shortest return path for signals and effectively shield against external interference. For complex boards like 48V System PCBs, which integrate both power and signals, a rational layer strategy is crucial.
• Placement of Critical Components: The layout of transceivers, common-mode chokes, termination resistors, and ESD protection devices has a decisive impact on EMC performance. We recommend placing these components compactly near connectors and ensuring short, thick grounding paths.

Get PCB Quote Test Purpose High/Low Temperature Operation ISO 16750-4 Verify functionality under extreme temperatures Temperature Cycling JESD22-A104 Evaluate fatigue failure caused by thermal mismatch of materials Mechanical Vibration & Shock ISO 16750-3 Simulate vibration and shock environments during driving Damp Heat Cycling IEC 60068-2-38 Evaluate CAF resistance in high-temperature/high-humidity environments Salt Spray Test IEC 60068-2-11 Evaluate corrosion resistance of surface treatment and solder mask