In AEC-Q100, the reliability qualification standard for automotive ICs, which ambient temperature range is specified for operating temperature Grade 1?

Answer: B. −40 to 125 °C

AEC-Q100 grades denote ambient temperature ranges; the smaller the number, the higher the upper limit. Grade 0 is −40 to 150 °C, Grade 1 is −40 to 125 °C, Grade 2 is −40 to 105 °C and Grade 3 is −40 to 85 °C. −40 to 150 °C is the most stringent, Grade 0, and −40 to 85 °C is the Grade 3 range. Because self-heating makes the chip's junction temperature higher than the ambient temperature, thermal design must also account for that difference.