Re: Simulation models for HMC699 (PLL) with HMC583 (VCO)

Question

Hi Huangzeyan, 
 Thank you very much for your useful answer. 
 I have still a couple of questions: 
 1) Which is the best opamp you may suggest to keep the phase noise as low as possible? 
 2) I am missing the reason why the phase detector gain is set to 2 V/rad in the main window. This is my reasoning: 
 a) Each port of the phase detector balanced output (UN and UD) swings 2 Vpp for 2pi radians. The balanced signal should thus swing 4 Vpp for 2pi radians, thus approx. 0,64 V/rad. Where am I wrong? 
 Thanks again and best regards. 
 Forum admin note, this question was branched from: 
 Simulation models for HMC699 (PLL) with HMC583 (VCO)

huangzeyan · Accepted Answer

Hi avilla, 
 
 1) ADA4084 is a good part which could keep a low phase noise performance. 
 2)Per the datasheet, the PFD gain here is 0.32V/rad. For synthesizers with PFD output, you could put 2 in the phase detector gain box. The software will take care of it. You could consider the box here s in unit Vpp/2pi. 
 
 Thanks.)

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Re: Simulation models for HMC699 (PLL) with HMC583 (VCO)