A High Efficiency and High Linearity GaAs HBT Doherty Power Amplifier for 5G NR 3.4V Application
This work presents a 3.3-4.2 GHz broadband two-stage fully differential Doherty power amplifier (DPA) for 5G new radio (NR) handset applications with low supply voltage 3.4V. It is implemented by 2-μm GaAs HBT Flip-chip process for PA and 6-layer laminate substrate process for output transformer and matching networks. For continuous-wave (CW) signal, the implemented DPA module exhibited a saturation power of 33.4 to 34.8 dBm, and PAE of 38 to 43% at full N77 band. Using the 5G new radio 100-MHz QPSK signal, this work shows high linear power of 31 dBm with 34% PAE and 30 dBm with 31% PAE at N78 and N77 band, respectively. The corresponding adjacent channel leakage ratios (ACLRs) are lower than -36.5dBc without digital pre-distortion (DPD). The chip size is only 1.1×1.3mm2, while the module area is 1.3×2.5 mm2.