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Automotive Semiconductors and Functional Safety

Learn the basics of automotive semiconductors — AEC-Q100 temperature grades, ISO 26262 ASILs with SPFM, LFM and PMHF, safety mechanisms such as lockstep, CAN and automotive Ethernet, load dump and SOTIF — through multiple-choice questions.

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Automotive Semiconductors and Functional Safety: key points

Automotive semiconductors are used for around 15 years at temperatures ranging from −40 °C to as high as 150 °C, and because their failures can endanger lives, they must meet stricter quality and reliability requirements than consumer parts. The foundation is qualification testing such as AEC-Q100, quality control aiming for zero defects, change notification and traceability.

Beyond that, ISO 26262 functional safety determines an ASIL from the magnitude of the hazard and uses safety mechanisms such as lockstep CPUs, ECC, and voltage and clock monitoring to detect faults and move to a safe state. You will learn the basics of automotive electronic design, from CAN and automotive Ethernet networks and 48 V and 800 V power systems to ADAS sensors and SOTIF.

All Automotive Semiconductors and Functional Safety questions (50)
  1. In AEC-Q100, the reliability qualification standard for automotive ICs, which ambient temperature range is specified for operating temperature Grade 1?
  2. Which correctly pairs AEC-Q100, AEC-Q101 and AEC-Q200, the qualification standards for automotive electronic components, with the components they mainly cover?
  3. Assume an automotive component operates continuously 24 hours a day for 15 years. Approximately how many hours is its total operating time?
  4. Which best describes the "zero defect" philosophy required for automotive semiconductors?
  5. Which correctly describes PPAP (Production Part Approval Process) used in the automotive industry?
  6. For an automotive semiconductor, which is the correct way to proceed when you want to change the manufacturing fab or the materials used?
  7. What is the main purpose of recording the lot number, wafer number and on-wafer coordinates during wafer test in electrically programmable non-volatile memory (such as fuses) inside an automotive IC?
  8. In qualification of automotive ICs, what is the main reason HAST (a biased test in pressurized water vapor at around 130 °C and 85% RH) is sometimes used instead of the temperature humidity bias test (THB) run at 85 °C and 85% RH for 1000 hours?
  9. Why are latch-up tests on automotive ICs required not only at room temperature but also at the product's maximum operating temperature?
  10. Which correctly describes the difference between component-level ESD tests of ICs (HBM and CDM) and system-level ESD tests performed on finished automotive equipment?
  11. Which correctly describes the functional safety standard ISO 26262?
  12. Which correctly describes the concept of automotive functional safety?
  13. In ISO 26262, which correctly lists the three factors evaluated when determining the ASIL through hazard analysis and risk assessment (HARA)?
  14. Which correctly describes the ASIL in ISO 26262?
  15. A hazardous event was assessed as severity S3, exposure E4 and controllability C3, giving ASIL D. If, for the same event, only controllability were C2 (most drivers can normally avoid the hazard), what would the ASIL be?
  16. Which correctly describes a "safety goal" in ISO 26262?
  17. Which correctly pairs the descriptions of random hardware failures and systematic failures as distinguished in ISO 26262?
  18. For PMHF, the metric for the probability that a safety goal is violated due to random hardware failures, the target guideline for ASIL D is less than 10 FIT. What is this expressed as a probability per hour?
  19. Which is the correct target guideline for the single-point fault metric (SPFM) required for ASIL D?
  20. Which is the most appropriate example of a latent fault in ISO 26262?
  21. The total failure rate of safety-related hardware is 1000 FIT, of which single-point faults and residual faults (faults that remain undetected by safety mechanisms) total 5 FIT. What is the single-point fault metric (SPFM)?
  22. A safety mechanism with 99% diagnostic coverage is added to a circuit with a failure rate of 200 FIT. What is the failure rate of the faults that remain undetected by the safety mechanism?
  23. Which correctly describes the fault tolerant time interval (FTTI) in ISO 26262?
  24. Which correctly describes how a lockstep CPU, used as a safety mechanism in automotive microcontrollers, works?
  25. What is the main reason for offsetting the execution of the two cores in a lockstep CPU by a few clock cycles, or placing the two cores apart on the chip?
  26. An automotive microcontroller's memory uses ECC (SEC-DED), which can correct 1-bit errors and detect 2-bit errors. What generally happens when read data contains a 2-bit error?
  27. Which correctly describes a feature of a window watchdog timer?
  28. What is the main functional safety purpose of running logic BIST and memory BIST in an automotive microcontroller at power-up or before driving?
  29. Which is an appropriate clock-monitoring safety mechanism for an automotive microcontroller?
  30. Which is an appropriate voltage-monitoring safety mechanism provided in functional-safety-compliant automotive power ICs and similar devices?
  31. In ISO 26262 ASIL decomposition, which combination is permitted for splitting an ASIL D safety requirement and allocating it to two sufficiently independent redundant elements?
  32. Which correctly describes SEooC (Safety Element out of Context) in ISO 26262?
  33. Which correctly describes FMEDA (Failure Modes, Effects and Diagnostic Analysis) performed in functional safety assessment?
  34. When the functions of multiple ECUs are integrated into a single high-performance SoC and software of different ASILs runs together, which is required?
  35. In CAN, what happens when two nodes start transmitting frames at the same time?
  36. On a CAN bus with 120 Ω termination resistors at both ends, the resistance between CAN_H and CAN_L was measured with the power off. Which value is closest to that of a normal bus?
  37. Which correctly describes a feature of CAN FD?
  38. Which correctly describes a feature of the in-vehicle network LIN?
  39. Which correctly describes a feature of the in-vehicle network FlexRay?
  40. Which correctly describes a feature of automotive Ethernet (100BASE-T1, 1000BASE-T1, etc.)?
  41. Which correctly describes the ongoing shift to a "zonal architecture" in automotive electronic systems?
  42. Which is the appropriate approach when performing an OTA (Over-the-Air) update, which rewrites vehicle software wirelessly?
  43. Which correctly describes the difference between the automotive standards ISO 26262 and ISO/SAE 21434?
  44. When the same power is delivered through wiring of the same resistance, by roughly what factor does the Joule loss in the wiring change if the supply voltage is raised from 12 V to 48 V?
  45. Which voltage class is commonly used for the power devices in the traction inverter of an electric vehicle with an 800 V battery?
  46. Which correctly describes "load dump," a problem in automotive power supplies?
  47. Which best describes how IGBTs, SiC MOSFETs and GaN HEMTs are chosen for power conversion in electrified vehicles?
  48. Which correctly describes a feature of millimeter-wave radar used in ADAS (advanced driver assistance systems)?
  49. A LiDAR takes 400 ns from emitting a laser pulse until the reflected light returns from an object. Approximately how far away is the object? (speed of light 3×10⁸ m/s)
  50. Which of the following problems is addressed mainly by SOTIF (ISO 21448, Safety of the Intended Functionality) rather than ISO 26262 (functional safety)?

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