Phase locked loop [ PLL ] require having lock timing less than 15us

Dear All,

I need PLL having lock timing less than 15us as one of my applications requires the lock timing should be less than 15us. Kindly suggest any PLL IC with integrated VCO .frequency ranges is V/UHF upto 3GHz or above?

Q2 Kindly suggest any PLL IC having 2 integrated ICs.

BR

Parents
  • +1
    •  Analog Employees 
    on Mar 9, 2021 12:45 PM

    Hello,

    To get a wide frequency range of operation, a lot of our PLLs with integrated VCOs use a multi band VCO and so there will be some time associated with selecting and changing the band. Internally, a VCO autocalibration engine is used to change the VCO band when a frequency change happens. It can take up to 10ms for the autocalibration to run depending on the PFD frequency (The frequency the ADC that the autocal uses is based on the PFD frequency).

    It is possible to bypass this autocalibration, if you know which band the VCO will need to be in for each frequency. This is accomplished by building up a table of the bands for each frequency and manually writing them to the PLL. We call this calibration bypass.

    Please see this document for more detail on calibration bypass:

    https://www.analog.com/media/en/technical-documentation/application-notes/AN-1353.pdf

    When using our PLL in calibration bypass mode, the settle time is then limited mostly by the loop filter dynamics. With a wide loop filter it will be possible to meet the 15us settle time. For designing your loop filter to meet your applications requirement's, I strongly recommend downloading our free software called ADIsimPLL. It will simulate lock time and help you choose a device and design an acceptable loop filter.

    The ADF4356 has a fundamental VCO frequency of 3.4GHz to 6.8GHz, but it can get lower frequencies as it has an output divider. I think this would be the best PLL to look at first. If you need better phase noise/jitter performance than this, then the ADF4372 is relatively similar but it a more recent release and has a much better FOM.

    If using an external VCO there are a lot of standalone PLLs of ours covering your frequency range. The product selection table is probably best to use. For a PLL with external VCO, if you have a fundamental VCO then there is no need for the autocal as described above, it is limited by LBW. Although I think it will be hard to find a fundamental VCO to cover the full frequency range. The ADF4150HV is probably a good option to look at as it has a wide tuning range charge pump, and also has a divided output which would help get your lower frequencies

    Regards,

    Alex

Reply
  • +1
    •  Analog Employees 
    on Mar 9, 2021 12:45 PM

    Hello,

    To get a wide frequency range of operation, a lot of our PLLs with integrated VCOs use a multi band VCO and so there will be some time associated with selecting and changing the band. Internally, a VCO autocalibration engine is used to change the VCO band when a frequency change happens. It can take up to 10ms for the autocalibration to run depending on the PFD frequency (The frequency the ADC that the autocal uses is based on the PFD frequency).

    It is possible to bypass this autocalibration, if you know which band the VCO will need to be in for each frequency. This is accomplished by building up a table of the bands for each frequency and manually writing them to the PLL. We call this calibration bypass.

    Please see this document for more detail on calibration bypass:

    https://www.analog.com/media/en/technical-documentation/application-notes/AN-1353.pdf

    When using our PLL in calibration bypass mode, the settle time is then limited mostly by the loop filter dynamics. With a wide loop filter it will be possible to meet the 15us settle time. For designing your loop filter to meet your applications requirement's, I strongly recommend downloading our free software called ADIsimPLL. It will simulate lock time and help you choose a device and design an acceptable loop filter.

    The ADF4356 has a fundamental VCO frequency of 3.4GHz to 6.8GHz, but it can get lower frequencies as it has an output divider. I think this would be the best PLL to look at first. If you need better phase noise/jitter performance than this, then the ADF4372 is relatively similar but it a more recent release and has a much better FOM.

    If using an external VCO there are a lot of standalone PLLs of ours covering your frequency range. The product selection table is probably best to use. For a PLL with external VCO, if you have a fundamental VCO then there is no need for the autocal as described above, it is limited by LBW. Although I think it will be hard to find a fundamental VCO to cover the full frequency range. The ADF4150HV is probably a good option to look at as it has a wide tuning range charge pump, and also has a divided output which would help get your lower frequencies

    Regards,

    Alex

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