upport Note SN026 presents a design example of an isolated RS-485 interface based on a 4-channel reinforced digital isolator[AB1] with integrated DC/DC converter. The design aims to reduce component count and PCB space while maintaining high electromagnetic compatibility (EMC) and communication reliability. It supports half-duplex operation at data rates up to 10 Mbit/s and complies with EMC standard CISPR 32 Class B.
Galvanic isolation effectively suppresses ground loops, transient voltages, and electromagnetic interference. The four-layer PCB structure incorporates overlapping copper areas to form integrated stitching capacitance, which improves common-mode noise immunity and overall EMC performance. Carefully selected filter components, protection diodes, and passive elements further enhance the robustness of the design.
The document provides detailed insights into component selection, layout structure, and conducted EMC testing. Results demonstrate that the design remains well below the required limits and is suitable for industrial applications demanding high reliability, safety, and communication quality.
Content:
Download: SN026
