Use of electronic systems in the vehicles is increasing day by day. As Electronic Control Modules (ECMs) become a large part of the vehicle, automotive designers need to take diligent decision of selecting electrical and electronic components. Selecting these components for ECM depends on four major factors: meeting stringent vehicle requirements, performance over the lifespan, robustness/reliability and cost. There is always an urge of reducing the cost of the ECM, but robustness of the controller module must not be compromised. One electrical or electronic component failure or false fault detection not only increases warranty cost but may also stall the vehicle, and interrupts customer’s daily routine creating dissatisfaction. This paper emphasizes on the importance of understanding worst-case operating scenarios considering component tolerances over the operating range, datasheet, and impact of tolerances on performance and fault detection. Wide ranges in component tolerances over worst-case operating conditions introduce challenges in optimizing circuit design over the operating environment. This paper exhibits real-life design examples that show the impact of non-ideal aspects of electrical and electronic components over worst-case operating scenarios on meeting the vehicle requirements, fault detection and safe operation. This paper also recommends some design considerations for robust circuit interface design. It is important to study component datasheets carefully to understand parameter variation impact on circuit performance and robustness. It is necessary that circuits are capable of surviving undetectable faults and reduce variation among multiple input power source.
