A 580-μW 13.8–16.2-GHz Series-Tank-Assisted Transformer-Based Oscillator Achieving -188 dBc/Hz FoM and 50 MHz/V Supply Pushing

This paper proposes a low-power digitally controlled oscillator(DCO) operating from 13.8 to 16.2 GHz. The DCO employs a self-biased inverter-based complementary Gm-cell with series capacitors that shield the main tank from the supply-dependent capacitance of the Gm-cell devices. This reduces the sensitivity to voltage supply variations. Additionally, the series capacitors form an auxiliary series tank along with the main parallel LC tank. As a result, it forms a complex tank with an enhanced Q factor, thereby lowering phase noise(PN). Fabricated in 28 nm CMOS, the proposed oscillator achieves -121dBc/Hz at 10 MHz offset from a 14 GHz carrier frequency. This results in an FoM of -188 dBc/Hz. Thanks to the proposed technique, the DCO exhibits a low supply pushing of 50 MHz/V, while maintaining the flicker corner <400 kHz across the tuning range (TR). The proposed work achieves a record-low power consumption of 580 μW in the >10 GHz category.