ADF4360-8 PLL - need suggestion to design loop filter

[UshaMaram]

adf4360 modulate

Iam working on ADF4360-8 synthesizer for a constant frequency of 120MHz.Iam not able to get the output and lock detect.i have uploaded the N,R and latch counter correctly with timings given as per data sheet. Can u suggest to design the loop filter to generate 120MHz of frequency

 

[kspalla]

adf4360-8

Tell us about the clock frequency and the values for NR etc.

 

[webdog]

ADF4360-8 PLL

You should really register to receive the Analog PLL design program...
http://forms.analog.com/form_pages/rfcomms/adisimpll.asp
And do not forget to read the tutorials. This will tell you all you need to know on how to design a loop filter for your 120 MHz oscillator. It is virually impossible for us to give any advice using the sparse data you provided. And designing a loop filter is really to do sound compromises, and only you know what compromises are suitable for you

/WD

 

[enkavak]

Re: ADF4360-8 PLL

Hello UshaMaram

Loop filter is required for elliminating the spurs which are generated by the PLL. the spurs can modulate the VCO and your carrier signal will deviate from what you want point. That is, you must get some frequency output regardless of the loop filter.
In addition, VCO defines the frequency output not the loop filter.

What do you get at the output of the VCO as a frequency?

Besides you should be more clear if you wanna help. Will you modulate an audio signal ? if so loop filter must be around 25KHz. However some low frequency spurs will interfere your audio signal and corrupt your audio.


engin