Design of LC-Tank Digitally Controlled Oscillator with Variable Capacitor

This paper proposes a 6-bit LC tuned digitally Controlled Oscillator (DCO) based on low-power and low-phase-noise. In this proposed design NMOS varactor weighing were implemented. The proposed DCO with capacitive degeneration oscillates at a frequency that can be tuned from 2.28-to-2.74 GHz with 20% tuning range. In proposed circuit we have achieved 6.33 mW power consumption at 1.8 V supply voltage and also achieved low phase noise that is −126.28 dBc/Hz at 1 MHz offset frequency.