A 10GHz Class-C Digitally-Controlled Oscillator with Fast Start-up Dynamic Biasing

A 10GHz class-C digitally-controlled oscillator (DCO) with fast start-up dynamic biasing is proposed. A feedback loop is used to detects the voltage of output common mode and control cross-couple pair from class-B to class-C operation. Moreover, the bias scheme uses a switching RC filter for fast start-up and low noise output. The proposed DCO is designed in 55 nm CMOS process, achieves a start-up time of 34 ns and a phase noise of -106.3dBc/Hz at 1MHz offset. DCO operates from 9.6 GHz to 10.5 GHz, while consuming 7.3mW from a 1.2V supply.