1.8 GHz CMOS LNA with on-chip DC-coupling for a subsampling direct conversion front-end

A 1.8 GHz CMOS LNA, which is suitable as a front-end in a direct conversion radio receiver, has been designed. The LNA is designed to drive a capacitive load such as the load of a subsampling mixer. The output resonator limits the mixer input noise bandwidth, which is necessary to optimize the system noise figure. DC-coupling, an essential function in a direct conversion front-end, is realized with an on-chip structure, which has low sensitivity to parasitic effects. The LNA achieves NF of 3.4 dB and gain of 17 dB from 3 V supply.