A SAW-Less Receiver Front-End Employing a Current-Mode RF Band-Pass Filter

In this paper, a SAW-less front-end with enhanced blocker filtering performance is presented. Two RF transconductance(Gm) units called notch Gm unit and all-pass Gm unit are employed to construct a current-mode RF bandpass filter. In notch Gm unit, N-Path filters are implemented in feed-back loop to achieve a notch characteristic transconductance and desired signal around LO will be filtered out. On the other hand, all-pass Gm unit provides a flat transconductance during the whole bands of interest. In output node, blocker will be cancelled due to subtraction of current in different RF transconductance units. This work prevents large voltage swings by operating in current mode and offer a higher ultimate blocker rejection ratio. Proposed Front-end is designed in TSMC 130nm standard CMOS process, and the Front-end can work under frequency from 1-GHz to 2.1-GHz, realizes <;7 dB NF, provides 42 dB conversion gain, achieves >42 dB stop-band rejection at 20 MHz offset while consuming 20 mW of power at 1.85-GHz.