Design and modeling of compact on-chip transformer/balun using multi-level metal windings for RF integrated circuits

A compact integrated balun transformer is analyzed that meets the size demand of highly integrated RFICs for the wireless industry. The design of a balun transformer with 4:1 impedance ratio using multi-level windings significantly reduces the silicon area compared to that occupied by an equivalent planar design. Its application is demonstrated in a highly efficient, linear amplifier design which achieved first pass design success.