Comparison of tunability and phase noise associated with injection locked three staged single and differential ended VCOs in 90nm CMOS

This work explores the injection locked single and differential ended ring VCO (Voltage Controlled Oscillator) suitable for a frequency synthesizer to operating over a wide range of frequencies with reduced phase noise. Along with design, the comparisons between 3 stage single ended and differential ended injection locked ring VCO topologies were studied. Single ended VCO was observed to have a tuning range of 1.2 to 3.6 GHz with phase noise of −110.2 dBc/Hz at 10 MHz offset and differential ended design have a tuning range of 1.5 to 3.1 GHz with phase noise of −109.9 dBc/Hz at 10 MHz offset. The injection locked VCOs were designed using 90 nm CMOS technology in ADS (Advance Design System).