Balun Transformers for Signal Circuits Murata Balun Transformers for Signal Circuits feature a fully closed magnetic circuit structure with wires wound around a two-hole core. The base pins are end-processed to allow direct mounting on PCBs. These surface-mount converters are used to smoothly connect balanced and unbalanced circuits. They utilize a Ni-Zn ferrite core with diallyl phthalate base, phosphor-bronze terminals with Ni/Sn plating, and polyurethane-system coated copper wire. Murata Balun Transformers for Signal Circuits are ideal for use in double-balanced mixers and as broadband transformers, transistors, and frequency mixers for cable modems.