A fully integrated 39.8-/43-GHz VCO - featuring wide tuning range and low temperature drift - for single-chip MUX/DEMUX LSIs

A fully integrated 39.8-/43-GHz switchable VCO was developed for practical single-chip MUX/DEMUX LSIs in 0.18 μm SiGe BiCMOS technology . The VCO provides a clock signal for data rates of 39.8 and 43.0 Gbps. The VCO has a novel configuration of a half-frequency VCO and a frequency doubler to realize a 7 GHz tuning range, for tolerating process deviation and supporting dual mode operation. A new temperature compensation technique resulted in a 0.6% temperature fluctuation of oscillation frequency. Measured phase noise at a 1 MHz offset frequency was -85.0 dBc/Hz. Data transmission experiments between the MUX and DEMUX confirmed that this phase noise is allowable for use in 40-Gbps class network systems.