A 38 GHz Low Power Variable Gain LNA Using PMOS Current-Steering Device and Gm-Boost Technique

In this paper, we present a low power variable gain LNA for 5G communication at 38 GHz in 90 nm CMOS process. Compared with traditional current-steering amplifier, proposed VGA is a three-stage current-steering amplifier and uses PMOS current-steering device to replace NMOS device. Using PMOS current-steering device can make the input and output impedance stable under gain switching. In addition, linearity isn't limited on current-steering device. Furthermore, we use the gm -boost technique to improve gain and cancel out parasitic capacitance. The measured peak gain is 18.89 dB at 36.5 GHz and 3-dB bandwidth is 34.7~39.2 GHz. Under different gain states, the peak gain is 18.89, 16.54 and 8.4, respectively at 36.5 GHz. The measured IP1dB is -20/-15/-7 dBm under different gain states. The measured lowest N.F. is 6.74 dB at 39 GHz at high gain mode. Total DC power consumption is only 15.62 mW for 2 V supplied voltage. To our best knowledge, this VGLNA has lowest DC power and compact area at Ka-Band.