A CMOS active balun using bond wire inductors and a gain boosting technique

Abstract

An active balun with a single-ended input and a pair of differential outputs is presented for the input stages of differential circuits. The active balun, which is composed of an input resonator and cascaded common-gate amplifiers, was implemented using 0.18-mu m CMOS technology and bond wire inductors. A body-source cross-coupled configuration was used to enhance the gain of the active balun. The gain is 9.3 dB at 1.8 GHz, and the phase and the amplitude error are less than 2 degrees and 1 dB, respectively, in the frequency range of 1 to 2 GHz, even for a P-1dB of -2.7 dBm. The balun consumes 9 mA for 3-V supply voltage.