1.3 V low close-in phase noise NMOS LC-VCO with parallel PMOS transistors

A new NMOS cross-coupled LC-VCO with parallel PMOS transistors is proposed. The proposed LC-VCO is useful for suppressing flicker noise upconversion and very suitable for low voltage application. It is implemented in 0.18 mum CMOS technology and has superior characteristics to a conventional complementary LC-VCO. Measured phase noise is -93 dBc/Hz at 100 kHz and -116 dBc/Hz at 1 MHz offsets and its core current is only 2 mA for a 1.3 V supply voltage.