Common mode chokes cut EMI in high-speed serial data links
Tsun-kit Chin, National Semiconductor - TechOnline - August 29, 2011
National Semiconductor's SerDes technology is explained here in detail.
Complementing widely used infotainment bus systems such as MOST or IEEE 1394, serial data links are increasingly used for point-to-point high-speed data connections in the infotainment realm.
Common mode chokes are widely used in such data transmission, especially when the transmission medium is a cable connecting two sub-systems, such as a serializer and deserializer (SerDes). These devices reduce electromagnetic radiation caused by unwanted common mode signals from the cable to obtain compliance with regulatory requirements.
Because the common mode chokes are directly in the data path, their electrical characteristics can impact the performance of the differential signal transmitted through the cable. This article outlines the construction, the electrical properties, specification, performance tradeoffs, and the common uses of common mode chokes—providing hardware engineers with information for selecting the correct components for a given application.
For the complete article, click here
, courtesy of Automotive Designline Europe.