EMC COMPLIANT RS-485 transceiver protection circuit

　　Circuit Function and Advantages

　　The circuit shown in Figure 1 uses the ADM3485E transceiver and is a proven and tested electromagnetic compatibility (EMC) solution that provides triple protection for the widely used RS-485 communication ports. Each solution is tested and characterized to ensure that the dynamic interaction between the transceiver and the protection circuit components works together to protect them from electrostatic discharge (ESD), electrical fast transients (EFT), and surges - defined by the IEC61000-4-2, IEC61000-4-4, and IEC61000-4-5 standards, respectively. This circuit uses the ADM3485E to provide proven protection for RS-485 interfaces from ESD, EFT, and surges (common in harsh operating environments).

　　Figure 1. Three EMC-compliant ADM3485E protection circuits (simplified schematic; not all connections shown)