A 28nm CMOS 1.3-GHz Low Phase Noise Gm-Boosted Cross-Coupled DCO for Automotive Radar Applications

Abstract

In this paper, the first Gm-Boosted Cross-Coupled DCO in a 28-nm CMOS technology for automotive radar applications is reported. The use of 28-nm CMOS technology poses new challenges on low phase noise DCO design. Supply voltages are further reduced to 0.9 V in order to not to damage the devices, resulting in a lower voltage swing and higher achievable phase noise with respect to higher supply voltage designs. In addition, very stringent local density rules, even required to meet in small inductor and capacitor areas, add an extra difficulty to layout a DCO, so the way the inductor is laid out becomes an essential step during the design to obtain the desired performances. The presented DCO achieves a phase noise equal to -127 dBc/Hz at 1 MHz offset from its central oscillation frequency of 1.3 GHz, achieves a tuning range of 1.25 GHz to 2.25 GHz with a fine frequency resolution of 1.1 MHz and consumes the total power of 5 mW using a 0.9-V supply. The layout area is 280 µm × 530 µm including the inductor. Finally, the tuning range-based Figure Of Merit (F OMT ) is equal to 194 dB.