Common Mode Chokes are designed to attenuate and filter common mode noise within an electric system.   The key parameters for a common mode choke are the current rating (to ensure the part does not overheat within the application), the impedance versus frequency (to ensure it is optimized to attenuate the desired frequencies), the isolation voltage (to ensure it meets board level requirements between the line and neutral phases) and safety isolation (to ensure it meets the safety requirements of the end-application).   It is important to remember that common mode chokes cannot saturate in the application (under normal use) as they are designed to ensure that the line and return currents are balanced.

small size,SMD Package