Integrated Circuits and Applications

A: Option A lines up with how field failures actually happen: noise couples through the harness and ground system, not the lab supply. Checking excitation first avoids chasing ADC errors that are really sensor supply drift, and measuring codes against INL while powered from a battery simulator exposes cranking and ripple effects. B feels tidy but hides the harness and ground offsets that kill you at 40,000 km. C is a classic QA move from wiring teams, but continuity doesn't tell you anything about ADC linearity under bias and noise. D sounds schedule-driven and familiar, yet it ignores that marginal ADC front ends create software ghosts you never fully calibrate out.

A: A accepts the ugly truth of the vehicle electrical environment: cold crank and load dump drive silicon stress, not steady-state efficiency. B looks defensible on paper, but TVS aging and thermal drift mean the LDO still sees repeated near-abs-max hits over life. C is a trap from adjacent power electronics work; fuses don't react on the timescale of load dump. D can work in clean industrial systems, yet the linear pre-dropper burns margin and heat during cranking, accelerating regulator wear.

A: A comes from first principles: typical θJA numbers for real ECUs, not datasheet fantasy. B borrows intuition from power electronics with heavy copper and airflow; most ECUs don't have that luxury. C assumes worst-case without scaling to actual dissipation and area, overshooting into alarmism. D sounds reasonable if you've lived in metal housings, but ignores that PCB-to-case resistance is often the bottleneck.

A: A matches the environment and the symptom timing: moisture plus bias equals slow, invisible damage. B happens outside the package and shows up differently. C is real, but you'd see it across climates, not clustered in coastal fleets. D scares everyone in board-level reliability, yet whiskers don't grow inside molded ICs the way this failure presents.