A 2-GHz FBAR-Based Transformer Coupled Oscillator Design With Phase Noise Reduction

• Published in: IEEE transactions on circuits and systems. II, Express briefs Vol. 66; no. 4; pp. 542 - 546
• Main Authors: Koo, Jabeom, Wang, Keping, Ruby, Richard, Otis, Brian P.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic coupling; Acoustic noise; Bulk acoustic wave devices; Capacitors; Current sources; FBAR; Film bulk acoustic resonators; Inductors; Noise; Noise levels; Noise reduction; Oscillator; Phase noise; Power consumption; Power demand; reference clock; Resonant frequency; transformer; Transformers
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2018.2867563

The oscillator architecture is proposed to reduce the close-in phase noise as well as power consumption. The proposed Colpitts oscillator removes the current source which is the main source of the 1/f noise conversion. The removal of the current source is compensated by using the transformer and cross-coupled capacitors. The 2-GHz film bulk acoustic resonator (FBAR) is used for the high Q frequency selective elements in the oscillator design. According to measurement results, this FBAR-based oscillator shows ≥ 10 dB reduction in close-in phase noise. Specifically, 12-dB lower phase noise is achieved at 100 Hz offset frequency. Measured power consumption is 350 uW, which is almost half of the conventional Colpitts oscillator using same FBAR device.