1.2–3.6 GHz 32.67 dBm 4096-QAM Digital PA Using Reconfigurable Power Combining Transformer for Wireless Communication

This paper presents a 1.2-3.6 GHz 32.67 dBm 4096-QAM CMOS digital power amplifier (DPA) with peak power added efficiency (PAE) of 35.5%. The reconfigurable power combining transformer with controllable impedance is introduced to achieve enhanced bandwidth. Meanwhile, the L-C circuit is utilized to suppress the 3
^rd
-harmonic and improve output power of fundamental signal. Besides, the 12-bit power digital-to-analog (power-DAC) with low LO leakage and large dynamic range is introduced to support high order modulation signals. The proposed wideband watt-level DPA is implemented in conventional 40-nm CMOS technology. It supports 50 MHz 256-QAM signal with 22.76 dBm average output power, 2.67% EVM, -30.67 dBc ACLR, and 1 MHz 4096-QAM signal with 24.08 dBm average output power, 0.67% EVM, -50.15 dBc ACLR, which is promising candidate for wireless communication.