A Dual-Core Dual-Mode DCO for S/C-Band Radar

This brief presents a dual-core, dual-mode digital-controlled oscillator (DCO) featuring a novel transformer-based resonator that minimizes parasitics in the switch connection lines and enhances the design flexibility of the resonator. Fabricated using 65-nm CMOS technology, the DCO occupies a die area of 0.76 mm2. Powered by a 1.2-V supply, it consumes between 6.6 and 10.8 mW of DC power. The DCO, utilizing a 127-bit thermometer-code switched varactor array (SVA), achieves a total bandwidth of 63.89%, spanning from 2.52 to 4.88 GHz. Over the entire frequency range, phase noise is measured between −116.14 and −119.34 dBc/Hz, resulting in a FoM ranging from −178.3 to −182.0 dBc/Hz, and a $\mathbf {FoM}_{\mathbf {T}}$ varying from −194.4 to −198.1 dBc/Hz. This DCO is well-suited as the frequency source for S-band and C-band radar applications.