Transformer Tank VCO Based on Inverse Class-F Architecture for mm-Wave Applications Using 180nm CMOS Technology

This paper introduces a differential output inverse class-F Voltage Controlled Oscillator (VCO) using PMOS-NMOS complementary configuration and a transformer-based two-port resonator to increase the voltage gain, whereas producing dual intrinsic-high quality impedance maximizes at the fundamental ( $f_{LO}$ ) and dual ( $2f_{LO}$ ) oscillation frequencies. The proposed inverse class-F VCO used the transformer-based tank to reshape the drain current and voltage waveforms and is designed in a 180 nm CMOS process for mm-wave and 5G applications. The proposed interleaved circular transformer achieves a coupling coefficient greater than 0.7, a high-quality factor of 22 and 15, and an inductance of 0.44 and 0.86nH at the primary and secondary inductors. The suggested VCO oscillates in between 26.5 GHz and 28.5 GHz and demonstrates a phase noise of -106 dBc/Hz at a 1MHz frequency offset. The figure of merit (FoM) equals -192 dBc/Hz and the peak obtained output power is -3.2 dBm. In the end, the VCO core area equals to 0. 09 mm ² whereas the overall chip size containing pads and output buffers equals 0.18 mm ² .