A low power and low noise frequency synthesizer with a integrated quadrature VCO

A frequency synthesizer including a integrated quadrature VCO and a few novel circuits is presented in a 0.18 um CMOS technology. A 16/17 dual modulus prescaler operates up to 5.1 GHz due to the fast (about 10 GHz) operation of the proposed complementary clocking (CC) dynamic flip-flop. Also, a phase frequency detector (PFD) utilizing the charge pump current feedback, generates low spurious tones irrespective of the temperature or supply variations. The measured reference spur is less than -120 dBc with a second order loop-filter of which bandwidth equals f_REF/50. The measured out- and in-band phase noise of the quadrature VCO is -140 dBc@8 MHz and -82dBc@10 kHz, respectively. With a 1.8 V power supply, the current consumption of the overall frequency synthesizer is only 7.5 mA except 50 Ω driving buffers.