A 40‐GHz hybrid class‐AB/class‐B CMOS VCO with a current‐combining transformer

• Published in: Microwave and optical technology letters Vol. 60; no. 6; pp. 1319 - 1323
• Main Authors: Oh, Juntaek, Jang, Jingyu, Hong, Songcheol
• Format: Journal Article
• Language: English
• Published: New York Wiley Subscription Services, Inc 01-06-2018
• Subjects: Circuits; class‐AB/class‐B; CMOS; current‐combining transformer; millimeter wave frequencies; Power consumption; Transformers; voltage controlled oscillator
• ISSN: 0895-2477; 1098-2760
• DOI: 10.1002/mop.31168

A 40‐GHz hybrid class‐AB/class‐B CMOS VCO with a current‐combining transformer (CCT) using a 65‐nm RF CMOS process is presented. The hybrid class‐AB/class‐B configuration is adapted to two cross‐coupled pairs to lower the power consumption while maintaining the phase noise performance. As a simple coupling network between two cross‐coupled pairs with different bias conditions, the CCT performs the roles of a high Q‐factor resonator, a large impedance transformer, and a buffer without additional circuitry. The VCO operates at 38.15–40 GHz with power consumption in the range of 11–13 mW. The measured phase noise at a 1‐MHz offset from the 40 GHz carrier is −117.1 dBc/Hz with a 1.0 V supply voltage. The proposed power oscillator achieves an FOMT value of −191.3 dBc/Hz.