A 6.4-8.5 GHz BiCMOS Power Amplifier with 24dBm Psat and 37.7% PAE in B55X for 5G-NR FR1 and 6G FR3 Dual-Band Application

This paper demonstrates a high-efficiency SiGe Power Amplifier (PA) for 5G New Radio (5G-NR) / 6G FR3 application. Four cascode cells are combined through current and pseudo-differential voltage combining at the output matching network to optimize power density, efficiency, and stability. A shunt neutralization inductor was added at the input of common-base transistors to absorb the $c_{be}$ parasitic capacitance of the stage and enhance output stability. This PA is implemented in the 55nm BiCMOS B55X process from STMicroelectronics with a total chip area of 1.42 mm2, The circuit achieves 24.1 dBm peak saturation power with 37.7% peak power-added efficiency (PAE) over the 6.4 to 8.5 GHz band with 49% of 3-dB fractional bandwidth (FBW). Tested at 7.5 GHz with 5G NR FR2 TDD modulated signals, this PA delivers up to 14.3 dBm of $\mathrm{P}_{\mathrm{o}\mathrm{u}\mathrm{t},\mathrm{a}\mathrm{v}\mathrm{g}}$ at 17.5^% $\text{PAE}_{\mathrm{a}\mathrm{v}\mathrm{g}}$, with -27 dB of rms EVM and -34.9 dBc of ACPR, for a l-CC 200 MHz 256 QAM showing 12.9 dB of PAPR.