A quarter-micron CMOS, 1 GHz VCO/prescaler-set for very low power applications

A VCO and a prescaler designed for wireless applications with very low power consumption requirements are presented. The VCO has a phase noise of -111 dBc/Hz at 100 kHz offset from a 1 GHz carrier and a tuning range of 18% while consuming only 250 /spl mu/A from a 2.5 V supply. The 64/65 dual modulus prescaler operates at the same frequency with only 0.9 mW. Both circuits are integrated in 0.25 /spl mu/m standard CMOS.