20-GHz PLL-based configurable frequency generator in 180nm SiGe-on-SOI BiCMOS

This paper presents a configurable frequency generator (CFG) capable of synthesizing frequencies between 10 MHz and 20 GHz with superior far-out phase noise of less than −150 dBc/Hz at 100 MHz offset when synthesizing >10 GHz, reference spurs less than −70 dBc, settling times of less 3 µs, and support for multiple reference frequencies through the use of a programmable bandwidth on-chip loop filter. The CFG is implemented in a 180nm SiGe-on-SOI BiCMOS process that enables high-frequency oscillation in the voltage-controlled oscillator (VCO), low parasitic switches for programmable passives, low phase noise HBTs, and excellent isolation between components sharing the same substrate.