DIFFERENTIAL TRANSFORMER USING BONDER-WIRES AND PATTERNS ON A PRINTED CIRCUIT BOARD FOR RF CIRCUIT APPLICATIONS

A transformer that uses bonder-wires and printed circuit board (PCB) patterns is proposed for RF circuit applications. The proposed transformer can be constructed without any additional processes. The PCB patterns are implemented using a typical FR4 substrate and gold bonder wires are used. The self-inductance of the transformer can be controlled according to the number of unit-transformers. Although the size of the transformer is larger than that of a fully-integrated transformer, the maximum available gain (MAG) is almost identical to that of other-types of transformers, which require additional cost or bulky size to obtain sufficient inductance. Additionally, we proposed a method to design the transformer with a symmetric structure for differential RF CMOS circuit applications. The transformer can applied to GHz-order RF CMOS circuits as an input and output matching component with low loss characteristics.