Abstract: As the importance of electrostatic discharge (ESD) protection capabilities gains increasing market recognition, traditional on-chip ESD devices are progressively failing to meet the growing ESD protection requirements for ports. To enhance product competitiveness, it has become imperative to improve the performance of on-chip ESD devices, particularly in automotive electronics. A series of customized requirements for on-chip ESD protection in applications such as in-vehicle bus systems, which demand substrate-direction voltage withstand capabilities, necessitates that such devices possess full isolation from the substrate. Addressing these port protection requirements, this paper proposes a universal modification approach based on standard devices in BCD (BipolarCMOS-DMOS) processes. This methodology enables designers to develop fully isolated Dual-Directional Silicon-Controlled Rectifier (DDSCR) structures that comply with port application requirements using standard device structure.