Title :
Transformer-Based Current-Reuse Armstrong and Armstrong–Colpitts VCOs
Author :
Keum-Won Ha ; Hyuk Ryu ; Joonhong Park ; Jeong-Geun Kim ; Donghyun Baek
Author_Institution :
Sch. of Electr. Eng., Chung-Ang Univ., Seoul, South Korea
Abstract :
This brief proposes two new types of current-reuse voltage-controlled oscillators (VCOs). One is a current-reuse Armstrong VCO (CR-AVCO) and the other is a complementary current-reuse Armstrong-Colpitts VCO (CR-ACVCO). Two one-transistor-based NMOS and PMOS AVCOs are combined into a complementary current-reuse form by sharing a transformer. The CR-ACVCO further improves the CR-AVCO by adding the Colpitts capacitive feedback, which has higher negative transconductance and, consequently, lower phase noise than that of the CR-AVCO. All the inductors are realized with one five-port transformer. The phase noise of the CR-AVCO and CR-ACVCO at 1-MHz offset frequency is -113.3 dBc/Hz at 4.84 GHz and -120.1 dBc/Hz at 5.3 GHz, respectively. The CR-AVCO and CR-ACVCO consume 2.32 and 2.74 mW from a 0.8- and 1.2-V supply, resulting in a high figure of merit with tuning range (FoMT) of -187.5 and -194.2 dBc/Hz, respectively. The proposed CR-VCOs are implemented in a 0.13 μm CMOS.
Keywords :
CMOS analogue integrated circuits; current transformers; phase noise; voltage-controlled oscillators; Armstrong-Colpitts VCO; CMOS implementation; Colpitts capacitive feedback; PMOS AVCO; five-port transformer; negative transconductance; one-transistor-based NMOS AVCO; phase noise; power 2.32 mW; power 2.74 mW; size 0.13 mum; transformer-based current-reuse Armstrong VCO; voltage 0.8 V to 1.2 V; voltage-controlled oscillators; CMOS integrated circuits; Frequency measurement; Logic gates; MOS devices; Phase noise; Tuning; Voltage-controlled oscillators; ${rm G}_{rm m}$ boosted; Armstrong; CMOS; colpitts; complementary; current reuse; voltage-controlled oscillator (VCO);
Journal_Title :
Circuits and Systems II: Express Briefs, IEEE Transactions on
DOI :
10.1109/TCSII.2014.2331112