Filtering EMI on an RS-485 Interface: Part I

By filtering directly at the interface, interference emissions, electrostatic discharges and fast transients bursts are prevented from entering the system; thus negatively influencing the operating performance. To verify the EMC properties of electrical systems, special tests are carried out in accredited EMC test laboratories, and if these tests are not passed, the application has to be revised. In order to simplify this process, an adapter stick was designed which contains a complete filter circuit for the selected application and can be plugged into the appropriate interface. Today's podcast is split in to two episodes. In part I of today's podcast, we will discuss the filter stick for the RS-485 transmission standard, how to correctly select the components, and finish with a discussion on the filter circuit of the supply voltage line. Download the complete Application Note, ANP008, at www.we-online.com/appnotes or click here. 

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