Large-Signal Analysis of a 1V Common-Gate with Common-Source Active Balun Circuit

An active balun (balanced-unbalanced) circuit is a type of transformer that converts signals that are single-ended or unbalanced with respect to ground into signals that are differential or balanced with respect to ground. Fig. 1 illustrates an active balun topology comprising of 2 amplifiers namely common-gate amplifier (M1) and the common-source amplifier (M2). The input signal is fed into the drain node or terminal of M1 and into the gate node of M2, while the outputs are probed at the drain terminals of M1 and M2. Load resistors R1 and R2 dictate the output voltages as well as the voltage gains of the two output signals with respect to the input signal.