A C/X-Band LNA Leveraging a Voltage-Tapered Gain-Cell Stacking Technique for 6G and IR-UWB

This work details the design of a low-power LNA, fabricated in a 45nm PDSOI process, for IR-UWB and 6G satellite communication applications. This device operates in C and X-band, demonstrating superb RF metrics compared to the state-of-the-art. Excellent performance is obtained via the adoption of an extremely power efficient topology leveraged at the amplifier’s input stage, whereby two complementary current re-use amplifier cells are stacked between the supply rail and ground. The amplifier cells share a common dc bias current, while their RF outputs are combined in parallel through capacitive coupling. This allows for bias current scaling with no penalty to voltage gain. The theoretical limit of gain-cell stacking is a function of supply voltage, input voltage swing, and the process dependent RF characteristics of a given device. Judicious consideration of these three factors can yield marked power savings, especially in a multi-stage design, where a tapered stacking approach may be implemented. This technique enables an exemplary LNA which demonstrates a peak gain of 24.1dB, 2.9GHz BW, a 4.5dB NF, and a OP1dB of 0.23dBm, while consuming 6.5mW of power. This equates to an excellent LNA FOM when compared to similar devices in the C and X-band.