A 6 GHz integrated VCO using SiGe BiCMOS process has been studied. The integrated inductors were realized by third metal with 3 µm thickness aluminum and its Q=20 at 6 GHz. The amplifier consisted of bipolar transistor. Tuning range was 38% with 0 V to 3 V tuning voltage. Phase noise of -100 dBc/Hz was obtained at 1 MHz offset from carrier frequency. The current consumption of VCO was 4.9 mA at 3 V power supply.

A scalable MOSFET parasitic model has been studied using 0.13 µm standard CMOS process. The model consisted of a core BSIM3v3 transistor model and parasitic resistor, capacitor, inductor, and diode. All parasitic components' values were automatically calculated by transistor geometrical parameters, only gate length (Lg), gate width (Wg), and gate multiple numbers (Mg), and some fixed process parameters such as sheet resistance of each part of diffusion layer. This model was confirmed for 0.25 µm to 0.5 µm gate length, 10 to 40 gate multiples with 5 µm gate finger width (Wf), 0.8 V to 1.5 V gate-source voltage (|Vgs|) with 0.6 V threshold voltage (|Vth|), and 1.0 V to 2.5 V drain-source voltage (|Vds|) from the viewpoint of small signal. The measured s-parameter and simulated one are in fairly good agreement in 200 MHz to 20 GHz frequencies range. This model is very simple, scalable, and convenient for RF circuit designers without difficult parameter setting.