We proposed a wide SOA and high reliability 0.35 μm CMOS compatible 100 V dual RESURF LDMOS transistor with low switching loss and low specific on-resistance for automotive applications. This paper describes detailed switching characteristics by changing load resistance R L and gate resistance R G for actual use which were not investigated. TCAD simulations verified that the total energy loss (total switching loss + conduction loss) of the proposed device is sufficiently smaller (about 30 % down at the maximum) than that of the conventional device in most of the actual use range except for the following region: low duty cycle D < 0.1 and high switching frequency f > 1.1 MHz at a low R G of 1.31 Ωmm 2 and a high R L of 65.5 Ωmm 2 under a device layout area of 1 mm 2 . Also, a unique switching characteristic of the proposed device, or a convex-shape gate plateau, not observed before, is analyzed.