Current reusing VCO and divide-by-two frequency divider for quadrature LO generation

For low-power and accurate quadrature local oscillator (LO) signal generation, an LC-tank voltage controlled oscillator (VCO) operating at double the required LO-frequency reuses the bias current of divide-by-two frequency divider. The current reusing VCO and divide-by-two frequency divider are targeted to generate the LO signals for a 1.57 GHz global positioning system receiver. Implemented in a 0.18 mu m CMOS technology, the current reusing VCO and divide-by-two frequency divider consumes 1.7 mA from a 1.8 V supply. The measured phase noise is - 120 dBc/Hz at 1 MHz offset when the carrier frequency is 1.57 GHz.