Dual-Mode CMOS RF Power Amplifier Design Using a Novel Reconfigurable Single-Switch Single-Inductor Balun

This paper presents a novel differential CMOS RF power amplifier (PA) design that can operate in either high-power (TIP) or low-power (LP) mode with enhanced efficiency. It is accomplished by the adoption of a newly developed low-loss, single-inductor, single-switch, reconfigurable output network for differential signal combining and impedance matching. For demonstration, the proposed PA with a center frequency of 2 GTIz is implemented using 0.35-μm CMOS process. Under continuous wave excitation, a power-added efficiency of 40.7% at 27.3 dBm in TIP mode and 34.2% at 21.9 dBm in LP mode can be obtained. In addition, under 3GPP WCDMA test without digital predistortion, measurement results (at 2 GTIz) indicate that the proposed PA module delivers an average output power of 24.1 dBm in TIP mode and 15.3 dBm in LP mode, at -33-dBc ACLR.