A 900 MHz RF transmitter with output LO suppression

Abstract

This letter presents a 900 MHz ZigBee RF transmitter front-end with on-chip LO suppression circuit at the output. To suppress the LO leakage at the RF output, a novel LO suppression circuit is adopted at the up-conversion mixer. The RF transmitter implemented in 0.18 mu m CMOS shows more than 28 dB of LO suppression over a wide range of the baseband signal power variation.