A 0.02–4.5-GHz LN(T)A in 28-nm CMOS for 5G Exploiting Noise Reduction and Current Reuse

In this article, a new noise reduction/cancellation technique is proposed to improve noise figure (NF) of a broadband low-noise transconductance amplifier (LNTA) for 5G receivers. The LNTA combines a common-gate (CG) stage for wideband input matching and a common-source (CS) stage for canceling the noise and distortion of the CG stage. Yet, another noise reduction is applied to reduce the channel thermal noise of the noise cancellation stage itself. The technique further exploits current reuse and increases transconductance of the CS transistor while keeping its power consumption low. Fabricated in 28-nm CMOS, the proposed LNTA is capable of driving an external 50-Ω load and achieves a NF of 2.09-3.2 dB and input return loss (S
₁₁
) better than -10 dB over the 3-dB bandwidth of 20 MHz-4.5 GHz while consuming 4.5 mW from a single 1-V power supply. The achieved gain (S
₂₁
) and IIP3 are 15.2 dB and -4.6 dBm, respectively.