This paper proposes a class-C digitally controlled oscillator (DCO) using constantly-conducting NMOS biased switchable capacitor, aiming to optimize the off-state quality factor, reduce the off-state capacitance and improve the oscillator transient behavior. The DCO is fabricated in a 28 nm CMOS technology. With a unitary-weighted SC bank, the DCO shows an inherently monotonic tuning with a range of 8.2-11.1 GHz (30.1%), and a very fine tuning resolution of 40kHz. The class-C DCO achieves -115.5 dBc/Hz phase noise at 1 MHz offset from 10 GHz carrier frequency with 23 mW, resulting in a -182 dBc/Hz FoM and -191.5dBc/Hz FoMT.

This work presents a reference frequency and current generator circuit with high stability to temperature and process variations without requiring any post-fabrication trimming. The design serves as the reference generator in an active gate driver IC for Silicon Carbide transistors. It incorporates an 8MHz relaxation oscillator and a 12μA self-calibrating current reference. Both circuits share a parallel-connected discrete off-chip resistor and capacitor to eliminate the impact of on-chip process variations. A temperature stability of 45ppm/°C for the frequency and 54ppm/°C for the current is achieved by applying a closed-loop comparator error feedback as well as a resistor temperature compensation. The overall frequency and current standard deviation for process variations is 0.70% and 0.47%. The circuit is fabricated in a 0.18μm BCD technology.

This paper presents a low-noise low-dropout regulator (LNLDO) implemented in a 28 nm technology. The LNLDO features a two-stage architecture, using a low-pass filter with a very low cut-off frequency to separate the regulation loop and the noisy devices such as resistive divider and bandgap reference. Supplied by a 1.5 V-1.8 V input voltage, the LNLDO is able to provide a stable output voltage ranging from 0.73 V to 1.71 V, with a current supply ability from 0 to 35 mA. An on-chip capacitance enhancer is used to stabilize the regulation loop without an additional external capacitor. The RMS noise from 10 Hz to 100 kHz of the LNLDO is below 20μV.