Project-on-Voltage-Controlled-Oscillators

Voltage Controlled Oscillator (VCO) design

This project shows the circuit design and simulation of a two-stage and four-stage Voltage Controlled Oscillators required in high-speed and wide bandwidth applications. The work has been performed at a supply voltage of 1.8V on 180nm technology on Cadence Virtuoso tool.

Schematic of 2-Stage VCO

The circuit is designed on 180nm technology on Cadence Virtuoso at supply voltage of 1.8V. The circuit uses NMOS varactors to obtain large tuning range for the control voltage. When the control voltage increases, the resistance of the PMOS and capacitances of NMOS increases and vice versa.

Simulations of 2-Stage VCO

Transient output waveform of the VCO at 1.8V supply voltage and 0.1V control voltage. Achieved a high oscillating frequency from 6.47-10.82GHz for 2-stage VCO with wide tuning range of 40.20%

The graph shows the noise analysis of the VCO at 1MHz frequency performed on Cadence Virtuoso ADEL.

This graph represents the phase noise simulation of the 2-Stage VCO at 1MHz frequency.

Schematic of 4-Stage VCO

4-Stage VCO is designed with four delay stages using NMOS varactors and provides lower oscillation frequency as compared to the 2-Stage VCO due to increase in the number of delay stages.

Simulations of 4-Stage VCO

Transient output waveform of the VCO at 1.8V supply voltage and 0.1V control voltage. Acheived high oscillating frequency from 4.23-7.06GHz for 4-stage VCO with wide tuning range of 40.08% with low power consumption.

The graph shows the noise analysis of the 4-Stage VCO at 1MHz frequency performed on Cadence Virtuoso ADEL.

This graph represents the phase noise simulation of the 4-Stage VCO at 1MHz frequency.