Hello everyone!
I'm working with ADF4159. Frequency of PFD 100 MHz. When I try to set out frequency 4.94 GHz I get 4.915 GHz. This situation I also see with frequency of PFD 50 MHz. When I work with frequency of PFD 25 MHz or less I see desired frequency 4.94 GHz. If I set INT = 49 and FRAC = 13 I see out frequency exactly 4.94 GHz. When I set INT=49 and FRAC =13421773 I get out frequency 4.915 GHz. What do I wrong way?
Loop filter was taken from ADIsimPLL, LFB = 250 kHz, phase margin 45 degrees. Icp=2.5 mA.