Design of a Tunable Multi-Band Differential LC VCO Using 0.35<mu>m SiGe BiCMOS Technology for Multi-standard Wireless Communication Systems

Official URL: http://www.elsevier.com/wps/find/journaldescription.cws_home/405904/description#description

In this paper, a 2.2-5.7 GHz Multi-band Differential LC Voltage controlled oscillator (VCO) for Multi-band Multi-standard is presented. The advantages of this VCO topology are 1) 5 controllable frequency bands, which is utilized by multi- standard, by the help of switching inductor and capacitor method 2) provide low phase noise performance by using all PMOS current sources topology which has minimum intrinsic and extrinsic sources of noise. The circuit is designed with AMS 0.35μm SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). According to the post layout simulation results, phase noise is -110.45dBc/Hz at 1MHz offset from 5.64 GHz carrier frequency, -119dBc/Hz at 1MHz from 3.95GHz carrier frequency, -121dBc/Hz at 1MHz from 3.5GHz carrier frequency, -121.2dBc/Hz at 1MHz from 2.7GHz carrier frequency and -122.5dBc/Hz at 1MHz from 2.27GHz carrier frequency. A linear, 1300 MHz maximum tuning range and 300 MHz minimum tuning range is obtained according to the post-layout simulations, by utilizing accumulation mode varactors. Output power of the fundamental frequency changes between -6.087 dBm and 0.992 dBm depending on the bias conditions (operating bands). Based on the simulation results, the core VCO circuit draws between 2.4mA-6.3mA current according to the frequency bands and 11.4mA-15.3mA from 3.3 V supply including buffer circuits leading to a total power dissipation of 34.2-50.5mW. Including DC, Digital and RF pads circuit layout occupies an area of 1.477mm2 on Si substrate.