Dear all!

**Is there any way to know how adisimpll calculate loop filter?**

**Is there any guide like "**Application Note 1001 by National Semiconductor."?

I am trying to design the loop filter of ADF4360-9 with next configuration:

FrefIN 10,00Mhz

Fvco 144.60

Phase detector frequency: 100KHz

loop bandwith: 10khz

Phase margin: 50 degree

Loop filter: CPP_3C

** **

** PROBLEM**:

I used ADISIMpll and i get next configuration Where could i find the equations ADISIMpll use for get this parameters?

C1=226pf

r1=13.2k

c2=3.91nF

r2=35.9k

c3=78.7pF

BUT i try to calculate by hand and i get ( i used book guide "PLL Performance, Simulation, and Design 3rd Edition Dean Banerjee")

C1=226pf

r1=14.79k

c2=3 nF

r2=5.1k

c3=510pF

THANK YOU.

I can't comment on the way you are designing the CPP_3C filter, but you can use ADIsimPLL to evaluate alternative designs, simply set the Loop Filter

Specifyparameter toComponentsand enter the alternative component values. ADIsimPLL will simulate the PLL performance with these values. In your case the values you give result in a Loop Bandwidth of 9.04kHz and a Phase Margin of 35.8 deg (cf your design of LBW=10kHz and PM = 50deg).Analyzing the CPP_3C filter is simple cicuit theory. Designing the CPP_3C filter is not quite as straightforward as it looks, partly as there are typically an infinite number of designs that all give the same transfer function. ADIsimPLL tries to choose a design that minimizes the phase noise. The algorithms in ADIsimPLL are an exact synthesis (you will get loop bandwidth and phase margin exactly as you specify). They produce similar results to the algorithm in:

Rosemarin, D

“Accurately Compute PLL Charge-Pump Filter Parameters”Microwaves and RF, February 1999, p89-94