White Paper: RF/Microwave PLLs Integrate Low Noise VCOs

One of the most common methods of generating a stable LO source is to combine a low phase noise voltage controlled oscillator (VCO) with a stable reference oscillator to form a phase locked loop (PLL) frequency synthesizer. Unfortunately, interactions between components within the PLL synthesizer, including the charge pump and loop filter, can offer challenges for the best designers, not to mention issues that arise due to circuit board layout and power supply noise. By leveraging our expertise in frequency generation components, Hittite Microwave has developed a line of PLLs with integrated VCOs to simplify the development of PLL-based frequency synthesizers.