A Low THD, Low Power, High Output-Swing Time-Mode-Based Tunable Oscillator Via Digital Harmonic-Cancellation Technique

• Published in: IEEE journal of solid-state circuits 2010-05, Vol.45 (5), p.1061-1071
• Main Authors: Elsayed, Mohamed M, Sanchez-Sinencio, Edgar
• Format: Article
• Language: English
• Subjects: Applied sciences; Band pass filters; Circuit properties; Circuits; CMOS; CMOS technology; Design. Technologies. Operation analysis. Testing; Digital; Digital filters; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Frequency filters; Harmonic cancellation; Harmonics; Integrated circuits; low THD; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Nanoscale devices; Noise levels; Nonlinear filters; Oscillators; Oscillators, resonators, synthetizers; Passive filters; Power harmonic filters; Prototypes; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; sinusoidal oscillator; Swing; time-mode systems; Tunable circuits and devices
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2010.2043885

An architectural solution for designing and implementing low THD oscillators is presented. A digital harmonic-cancellation-block is used to suppress the low-frequency harmonics while a passive, inherently linear, filter is used to suppress the high-frequency ones. The proposed technique eliminates the need for typical high-Q BPF to suppress the harmonics. Thus, eradicates the effect of increasing device nonlinearities in the nanometric technologies by having pure digital solution. In addition, eliminating the need for high-Q band-pass-filter (BPF) releases the output swing from the constraints imposed by the linearity of the filter. The prototype is fabricated in 0.13 ¿m CMOS technology. Measurement results show -72 dB THD at 10 MHz along with a differential output swing of 228 mV pp . The oscillator prototype can be tuned from 5 MHz to 11 MHz with less than 4.5 dB variations in the THD. The circuit consumes 3.37 mA from 1.2 V supply at 10 MHz and occupies an area of 0.186 mm 2 . As the performance depends solely on the timing precision of digital signals, the proposed oscillator is considered the best time-mode-based oscillator in literature.