The paper presents a study of common-source/drain active balun circuit in terms of the dynamic range, implemented in a complementary metal-oxide semiconductor (CMOS) technology. Dynamic range can be derived using noise analysis, and is an important design consideration since it determines the susceptibility of the active balun to unwanted signal or noise. Henceforth, it is critically important that the common-source/drain active balun circuit contributes as little noise as possible in the system level design of radio frequency (RF) applications. Furthermore, design tradeoffs are inevitable and are carefully considered in the analysis and design.