Overview
Products in automotive electronics are generally more expensive, in part because they use automotive-grade electronic components. What exactly qualifies as an automotive-grade component? First, compare how electronic components are used in vehicles versus typical consumer electronics.
Environmental requirements
Temperature: Automotive electronics have wider operating temperature requirements. The exact range depends on installation location, but requirements are generally more stringent than for consumer products. For example, AEC Q100 no longer includes the 0°C–70°C range in the H grade because no automotive product is expected to be limited to that range.
Typical examples:
- Around the engine: -40°C to 150°C
- Passenger compartment: -40°C to 85°C
- Consumer products: 0°C to 70°C
Other environmental factors such as humidity, mold, dust, water, EMC, and corrosive gases are often more demanding than for consumer electronics.
Vibration and shock
Vehicles operate in motion and expose components to significantly more vibration and shock than products intended for home use. These mechanical stresses can be much higher than those for consumer devices.
Reliability
Automotive reliability requirements are notably strict. Consider two points: 1) Design life: a typical vehicle is designed for around 15 years or 200,000 km, far longer than most consumer products. 2) The more components and subsystems a system has, the higher the reliability required of each part to achieve the target system reliability. Modern vehicles contain many electronic systems from powertrain to braking, each composed of many electronic components. If these elements are treated as a series chain, achieving overall vehicle reliability requires very high reliability for each component. This is why automotive parts are often specified in PPM (parts per million).
Consistency requirements
Mass production of vehicles demands very high quality consistency. Early on, maintaining process uniformity for semiconductor fabrication was challenging, leading to performance dispersion and reliance on burn-in and screening. Process improvements have since greatly increased consistency. Quality consistency is often the largest difference between local suppliers and well-known international suppliers. In complex automotive assemblies, components with poor consistency that introduce safety risks are unacceptable.
Manufacturing process
Although automotive parts are trending toward miniaturization and lightweight design, compared with consumer products they often allow more relaxed constraints on size and power. Larger packages are commonly used to ensure sufficient mechanical strength and to align with major automotive suppliers' manufacturing processes.
Product lifecycle
Vehicles remain durable goods and require long-term aftermarket parts supply. Developing an automotive part requires substantial validation work; changing components triggers extensive revalidation. Therefore, OEMs and suppliers need long-term stable supply arrangements.
Standards
Translating vehicle-level requirements into component-level requirements is complex. To address this, industry standards have emerged. The commonly recognized standards include:
- AEC Q100: requirements for active devices
- AEC Q200: requirements for passive devices
Vehicle manufacturers also have corporate standards that specify reliability for complete automotive assemblies rather than directly for individual electronic components such as resistors, capacitors, transistors, or ICs. Such corporate standards can guide component selection, but they are often not suitable as direct test specifications for components.
Automotive qualification
In practice, engineers sometimes use components without AEC Q100/Q200 certification and request reliability testing to assess suitability. However, these ad hoc tests are generally necessary but not sufficient. They can disqualify unsuitable parts but cannot conclusively prove suitability, because sample sizes and test scopes are usually inadequate. For semiconductor devices produced in large volumes, relying on a few samples to determine overall reliability is unreliable. Reviewing the full AEC Q100 test suite highlights the differences in rigor.
Which standard is stricter?
Common wisdom ranks standards as: military > automotive > industrial > consumer electronics. However, this hierarchy is not absolute. The industrial category covers a wide range of applications and environments. For example, critical equipment in a large power plant may demand reliability and environmental hardness that exceed automotive requirements. Therefore, it is not always correct to assume industrial standards are lower than automotive requirements.
Drawbacks of using automotive-grade parts
No choice is without trade-offs. Using automotive-grade components has several drawbacks. First, cost: the qualification system, validation effort, and generally lower volumes raise costs significantly compared to consumer electronics. Higher entry barriers also create a sales premium. Second, limited selection: many functions can be implemented by multiple component options with varying levels of integration and complexity, but meeting automotive requirements may force designers to avoid highly integrated solutions. Third, slower technology adoption: extensive validation can delay new products, and semiconductor vendors often introduce technologies in the consumer market before moving them into automotive applications.
How risky is it to use non-automotive components in vehicles?
The risk depends on multiple factors:
- If a component lacks formal certification but its performance and reliability are demonstrably sufficient and it has undergone extensive field validation, the risk is relatively low.
- The relationship between component and system is critical. System performance and reliability are determined by component behavior. With the same design, using non-automotive components usually results in a weaker product. But good system-level design can reduce component performance requirements. Robust protection and graceful-failure designs can allow non-automotive components to be used safely. Some components required for certain vehicle functions cannot meet full automotive specs due to current process limitations; they may still be necessary and can be used with system-level mitigations. Two cases illustrate this:
- High safety requirement, no tolerance for deviation. Example: an emergency call (E-CALL) system may require a backup battery to ensure operation. If the system must meet ASIL B (ISO 26262), batteries that maintain high performance at -40°C are difficult. One solution is to wrap the battery with a heating resistor to maintain performance at low temperature. A single component may not meet automotive specs on its own, but the assembly can meet vehicle OEM requirements. This illustrates the relationship between OEM corporate standards and component standards.
- Function not safety-critical, deviations are acceptable. Example: an infotainment LCD may exhibit degraded response or optical performance at low temperatures. Many engineers accept this behavior.
- There is also the risky approach of attempting to reduce cost or achieve better performance by validating a non-automotive component with a small sample size over a short period. That approach is unreliable and effectively leaves outcomes to chance.
