A V-band digitally controlled low noise variable gain amplifier with 3.5° phase variation in 28-nm bulk CMOS

Authors：Lin, Haitao; Li, Hui-Yang^*; Xu, Jin-Xu; Zhang, Xiuyin

Source：MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 2023, 65(9): 2488-2493.

DOI：10.1002/mop.33733

• 28-nm CMOS
• low noise amplifier
• low-phase distortion
• variable gain amplifier

This paper presents a V-band digitally controlled low noise variable gain amplifier (LNVGA) in 28-nm bulk CMOS process. The amplifier includes three stages and the first stage is used to realize wideband high gain and low noise figure (NF). The gain control is implemented in the second and third stages with current steering and split cascode topology, respectively. A source degeneration inductor and a series inductor are introduced to reduce the phase variation in the second stage. The phase response function is analyzed, and the phase reduction of 1.2 degrees is achieved. Moreover, with the combination of these two different topologies, the phase variation can be further reduced. The measurement results show the LNVGA has a peak gain of 16 dB with a 3-dB bandwidth of 45-59 GHz. The measured gain control range is 0-16 dB in 16 different gain states and the minimum phase variation is 3.5 degrees with power consumption of 23 mW.