hmc439 loop filter design

I am interested in using the HMC439 Phase-Frequency Detector (PFD) for a PLL application. Our application needs different VCO and narrower loop filter than the one shown in the datasheet (page-7, application circuit). I am not able to find a PLL design tool that will help me plug-in PFD gain/ offset, VCO parameters or loop-bandwidth requirements to calculate RC component values for the loop filter. I downloaded one PLL design tool from Hittite but it does not have a HMC439 PFD model.

I would appreciate any help in designing custom PFD + Loop filter using HMC439 + THS4031 with any off-the-shelf VCO modules.



  • Thanks for the prompt reply! I wasn't aware that this part wasn't recommended for phase detector applications!Unfortunately this is a legacy design and I'm looking to improve the loop response in the short term. I will investigate your recommendation of using a mixer on the next re-spin. I'm a little confused on how to convert  degrees/V into the required MHz/V for the PLL tool without knowing the rate of phase change. The operating frequency is 110MHz, and the phase detector sensitivity is 50Deg/V. Any suggestions?

  • 0
    •  Analog Employees 
    on Aug 2, 2018 2:52 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

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    EZ Admin