An ultra-low-voltage Class-C PMOS VCO IC with PVT compensation in 180-nm CMOS

A novel 2.2-GHz-band ultra-low-voltage Class-C PMOS VCO IC with negative reference and amplitude feedback loop is proposed. The negative reference initially adapts a sufficient bias for the LC-VCO circuit to ensure a robust oscillation start-up. The feedback loop then adaptively controls the bias condition of LC-VCO for Class-C operation in steady-state. The reliability of the feedback loop is enhanced over PVT variation. The Class-C VCO IC has been designed, fabricated and fully evaluated in 180-nm CMOS technology. The fabricated VCO IC exhibits a measured phase noise of -113.2 dBc/Hz at 1 MHz offset from the 2.2 GHz carrier frequency with a supply voltage of only 0.3 V.