A new modeling method is proposed to estimate the electromagnetic noise effects on an ADC in the electric vehicle. We focus on two noise sources; one is the switching noise from the automotive inverter. Second is the magnetic coupled noise from power circuit such as wireless power transmission. The ADC is fabricated using a 0.13-μm CMOS process, and the ADC is designed with a 4-layer stack-up PCB. The proposed model dramatically reduces the necessary computation time and resources without losing estimation accuracy. The proposed model is a new approach to the automotive semiconductor EMC.