TY - JOUR
T1 - Tuning Range Extension of a Transformer-Based Oscillator Through Common-Mode Colpitts Resonance
AU - Shahmohammadi, Mina
AU - Babaie, Masoud
AU - Staszewski, Robert Bogdan
PY - 2017
Y1 - 2017
N2 - In this paper, we propose a method to broaden a tuning range of a CMOS LC-tank oscillator without sacrificing its area. The extra tuning range is achieved by forcing a strongly coupled transformer-based tank into a common-mode resonance at a much higher frequency than in its main differential-mode oscillation. The oscillator employs separate active circuits to excite each mode but it shares the same tank, which largely dominates the core area but is on par with similar single-core designs. The tank is forced in common-mode oscillation by two injection locked Colpitts oscillators at the transformer's primary winding, while a two-port structure provides differential-mode oscillation. An analysis is also presented to compare the phase noise performance of the dual-core oscillator in common-mode and differential-mode excitations. A prototype implemented in digital 40-nm CMOS verifies the dual-mode oscillation and occupies only 0.12 mm2 and measures 56% tuning range.
AB - In this paper, we propose a method to broaden a tuning range of a CMOS LC-tank oscillator without sacrificing its area. The extra tuning range is achieved by forcing a strongly coupled transformer-based tank into a common-mode resonance at a much higher frequency than in its main differential-mode oscillation. The oscillator employs separate active circuits to excite each mode but it shares the same tank, which largely dominates the core area but is on par with similar single-core designs. The tank is forced in common-mode oscillation by two injection locked Colpitts oscillators at the transformer's primary winding, while a two-port structure provides differential-mode oscillation. An analysis is also presented to compare the phase noise performance of the dual-core oscillator in common-mode and differential-mode excitations. A prototype implemented in digital 40-nm CMOS verifies the dual-mode oscillation and occupies only 0.12 mm2 and measures 56% tuning range.
KW - Colpitts oscillator
KW - Common-mode oscillation
KW - inductor-capacitor (LC) tank
KW - transformer
KW - wide tuning range
UR - http://resolver.tudelft.nl/uuid:32ad43c4-23ff-41d1-9601-e65d9c9bc71c
UR - http://www.scopus.com/inward/record.url?scp=85015648312&partnerID=8YFLogxK
U2 - 10.1109/TCSI.2016.2625199
DO - 10.1109/TCSI.2016.2625199
M3 - Article
AN - SCOPUS:85015648312
SN - 1549-8328
VL - 64
SP - 836
EP - 846
JO - IEEE Transactions on Circuits and Systems Part 1: Regular Papers
JF - IEEE Transactions on Circuits and Systems Part 1: Regular Papers
IS - 4
M1 - 7876717
ER -