A 4-octave tuning range integer-/fractional-N synthesizer for low phase noise space applications

In this paper a low phase noise frequency synthesizer is presented which includes a fully integrated VCO system achieving a 4 octave tuning range between 220-3500MHz. Further, the phase locked loop (PLL) offers various configuration modes to flexibly support different applications with a single chip containing PLL and VCO. The PLL can operate in fractional- and integer-N mode. For the potential use in space missions the IC has been fabricated on a radiation hard process. The synthesizer architecture is discussed and details about selected building blocks are given. The paper concludes with a measured performance summary, which shows achieved values for the normalized inband PLL phase noise floor as low as -221dBc/Hz. This very low phase noise has been achieved despite the mature process and the applied derating rules.