A surface mounted pulse transformer (100) comprising a drum core (1) and a number of coils (3). The drum core includes a core (11), a first flange (12a) and a second flange (12b) disposed on both ends of the core. The number of coils wind around the core to form a primary coil and a secondary coil. A number of electrodes (40) are formed on surfaces of the first and second flanges and to be connected to an external substrate. The ends of the coils are physically and electrically connected to the electrodes. One of the electrodes has an electrode groove (401) for receiving and positioning one end of the coils.