A 40 GHz Quadrature LC VCO and Frequency Divider in 90-nm CMOS Technology

This paper presents the design of a fully integrated wide-band low phase noise quadrature LC-tank VCO and high-speed frequency divider in a standard 90nm CMOS technology. The LC oscillator has a differential core with complementary cross-coupled MOS devices. The oscillation frequency can be tuned from 31GHz-41GHz, with a control voltage between 0 and 1V. The quadrature VCO draws a maximum of 6.5mA current from a 1.2V supply. The divider core is formed with low voltage swing current mode logic (CML) structure, which enables high frequency operation at very low power dissipation. The divider exhibits very wide locking range from 4GHz-41GHz, and it has an input sensitivity of -31dBm at 30GHz. The divider core draws only 750muA from a 1.2V supply. Both circuits occupy a chip area of about 150 times 250mum².