Low supply voltage fully integrated CMOS VCO with three terminals spiral inductor

The very low phase noise and very low supply voltage 1.4 GHz CMOS VCO has been realized by 0.25 µm standard CMOS technology without any trimming and any tuning. The phase noise characteristics are achieved approximately -100 dBc/Hz at 100kHz offset with 1.3V power supply. To reduce supply voltage, the amplifier topology is consisted one pair of PMOS differential stage with special shapes of coil structure which is three terminals on chip spiral inductor. To reduce a flicker noise component coming from current source of the amplifier, the very large current source transistor is adapted.