A two-point tuning VCO with switchable secondary tuning gain K VCO2 is designed in 65nm CMOS for a two-point modulation PLL-based phase modulator that is to serve as phase-modulating part of a quad-band GSM/GPRS/EDGE polar transmitter. The two-point tuning VCO employs two varactor banks for dual tuning capability. The second varactor bank is a differentially tuned structure and its gain K VCO2 is switchable to minimize its variation for maintaining optimum second-point modulation gain. Fabricated in 65nm CMOS, the VCO draws 8 mA from 2 V supply. It covers the 2930 -4150 MHz. The phase noise is -142dBc/Hz at 10MHz offset for 3.9 GHz output frequency. The silicon area of the VCO and accompanying dividers is 810 x 600 Pm 2 .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.