• RE: ADF4155 frac-N PN Floor PLLsim vs Datasheet?


    The FOM numbers in the datasheet are the ones to go by. I checked the ADIsimPLL ADF4155 model code and it does look like it's using Frac FOM = -223 which is in incorrect, we should have this fixed for the next simPLL release.



  • ADF4155 register settings

    Programming the ADF4155.

    Using the register maps in the ADF4155 data sheet to calculate the required setting; the results all agree with the settings generated by the Eval Software except for register 6.This show a discrepancy that appears due to the…

  • ADF4155 Int-N Mode

    Hi ADI people,

    Unlike ADF4159, there is no explicit control bit to disable the Σ-Δ modulator in ADF4155. Can ADF4155 be operated in true int-N mode? In the datasheet, it says: "If FRAC1 and FRAC2 = 0, the synthesizer operates in integer-N mode"…

  • ADF4155 Σ-Δ Reset


    Could Σ-Δ Reset feature be available for ADF4155 like ADF4159 has (DB14 in R3)?



  • ADF4155: output stage

    Dear support.

    Regarding the ADF4155, I want to use this chip in my new design in order to realize an integer-N PLL with an external VCO. The VCO works in the range 4200MHz to 4360MHz, with an output level of about +4dBm.

    In order to implement the Mute…

  • ADF4155 IBS Characteristics


    I have a couple of questions from the customer. He is using ADF4155 Evalation board.

    1. Fig.9 shows the IBS characteristics of ADF4155.   He wants to know the more detailed conditions about Fig.9.
        Is it possible to let me know the more detailed conditions…

  • ADF4155 ref input

    Is it acceptable to feed the ref input to the ADF4155 with a single ended source? I assume I can just AC couple to ground the ref- pin? Any tradeoffs with doing this vs. using a true differential input?

  • ADF4155 Phase Noise

    We are finding in a lot of 10 modules that a very narrow phase noise problem occurs with the ADF4155 when locking to 4.8 to 5.6GHz.  When a unit has a problem it may only be 5MHz wide or perhaps 40MHz wide, usually just 20MHz wide.   The phase noise will…

  • ADF4155 reference input

    I am using a ADF4155 synthesizer. For the reference I have a crystal oscillator with a CMOS 3.3 V output.

    Is it correct to connect (ac coupled) directly the oscillator to REFIN+, in single-ended ? Do I need a filter ?

    Is it good in term of phase noise…

  • ADF4155 Eval software complaint...

    Really? In 2018? People are talking about autonomous driving, but no routine to handle regional settings? :/

    Depending on security policy set by the IT dept, not everyone can change these settings.