A digitally controlled oscillator with wide frequency range and low supply sensitivity

This brief presents a wide frequency range digitally controlled oscillator (DCO) with low supply sensitivity and low power consumption. We propose a compensation scheme employing feedforward inverters to suppress supply noise. Both wide frequency range and fine resolution are obtained using a hierarchical architecture consisting of a coarse delay chain and an interpolator. The proposed DCO was fabricated in a 0.13- μm CMOS process. It successfully eliminates noise components due to supply variation. The phase noise at 1-MHz frequency offset from the carrier frequency of 700 MHz is -106.3 dBc/Hz. The frequency range of the DCO is measured from 320 MHz to 1.25 GHz.