A 0.5V 0.18µm CMOS LC-VCO with a novel switched varactor technique

Abstract

A 0.5V LC-VCO implemented in 0.18µm CMOS with a novel switched varactor technique is described in this paper. This novel switched varactor technique can increase the varactor control voltage variation range and increase Q of LC tank; also it can reduce phase noise and power consumption of VCO. Forward-body bias technique is used to reduce the threshold voltage and improve g_m of transistor. The measured operating current is 4.4mA and the tuning range is 4.6∼5.2GHz. The phase noise is −114dBc/Hz at 1MHz from carrier frequency 4.8GHz.