A high reliable low noise frequency synthesizer design

A high reliable and low noise frequency synthesizer was designed and manufactured by 0.18um SiGe BiCMOS process. The innovation of this paper is to use HBT with better 1/f noise performance to replace MOS transistor to obtain better noise performance. The frequency synthesizer circuit is capable of producing 1.7GHz-2.3GHz RF output signal (one of the VCO output bands); The operating frequency of the frequency synthesizer is 800MHz-5GHz. The normalized phase noise of the frequency synthesizer reaches -230 dBc /Hz.