A 24.7 to 42.2GHz Tuning Range Quad-Core Triple-Mode VCO Using
Inductor-Sharing Technique
Abstract
The voltage controlled oscillator (VCO) with a wide tuning range
and low phase noise is extensively employed in domains such as 5G, 6G,
and satellite communication. This article commences with the phase noise
model to conduct an analysis of the multi-core VCO. Subsequently, the
mode switching technology is elucidated. On this foundation, an X-shape
compact equalizing on-chip transformer design based on the inductor
sharing technique is proposed. The transformer with three modes is
devised to enhance the output frequency range of the VCO. Distinct from
the traditional capacitive coupling, the alteration of the effective
inductance value is accomplished through the coupling between the
inductors to complete the regulation of the oscillation frequency range.
The proposed VCO structure adopts the 40nm process, achieving a 52.02%
continuous frequency tuning range from 24.7GHz to 42.2GHz. When the bias
is at 10 MHz, the phase noise varies within the range of -123dBc/Hz to
-132dBc/Hz, while FoM and FoMT respectively fluctuate
from 177dBc/Hz to 193dBc/Hz and 191dBc/Hz to 208dBc/Hz. Both
phase noise and FoM are improved and the area is only 0.057
mm2.
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