Design and implementation of an inductorless digitally controlled oscillator based on CMOS inverters

This paper presents the architecture of a digitally controlled oscillator (DCO) suitable for multi-standard radio frequency (RF) operation. The presented oscillator has an LC topology using an active inductor based on CMOS controllable inverters. The tunability of the oscillator frequency is ensured by varying the digital word applied to the inverters control voltages. The oscillator can cover different frequency bands from 1.23 GHz to 2.46 GHz by varying digitally four inverters sequence. It consumes less than 4.4 mW under 1.1 V supply voltage. It occupies a chip area of (54 × 59) μm2 in 130 nm CMOS technology.