This document describes the protection circuits for ADM3485E, an EMC compliant RS-485 transceiver, including two different protection schemes. The transceiver features ±15 kV ESD protection, 3.3 V, and 12 Mbps.
The document presents Circuits from the Lab™ reference circuits engineered to solve analog and mixed-signal design challenges. It details three distinct EMC-compliant protection schemes designed specifically for the ADM3485E RS-485 transceiver to protect against electrostatic discharge (ESD), electrical fast transient (EFT), and surge events.
The text describes an evaluation board, EVAL-CN0313-SDPZ, which integrates three ADM3485E devices, each configured with a different protection topology. The schemes utilize components such as TVS diodes, Transient Voltage Suppressor/Transient Burst Unit (TBU), and Gas Discharge Tubes (GDT) to achieve varying levels of surge immunity up to 6 kV while maintaining standard ESD protection.