Hi, I want ADF4350 to generate frequencies from 1.1GHz to 1.3 GHz (sweep). I want a single frequency at a time. I am programming ADF4350 using a PIC microcontroller. Following are the details:
REFin = 16 MHz (TXC oscillator; IC pin coupled through a 1 nF capacitor)
Rset = 5.1 k Icp = 5 mA
Low noise mode Cycle slip reuction DISABLED
Clock div mode OFF
Output frequency required : 1.1 GHz FRAC-N synthesizer
output divider : 2 Feedback signal: Fundamental
Prescaler : 8/9
F_pfd = 16 MHz
Band select clock divider = 128 Ref doubler and divider OFF
MOD = 130 INT = 137 FRAC = 65
Register values R5 = 0x00 58 00 05
R4 = 0x 00 98 04 34
R3 = 0x 00 00 00 03
R2 = 0x 0C 00 5E 42
R1 = 0x 08 00 84 11
R2 = 0x 00 44 82 08
The loop filter is designed for a bandwith of 10kHz using ADIsimPLL. The pll file is attached.
Since the exact component values were not available, I have used near values:
C1 = 40.5nF -->47 nF
R1 = 81 --> 82
C2 = 550 nF --> 470 nF
R2 = 166 --> 180
C3 = 18.5 nF --> 22 nF
With all this I am not getting even the expected R counter output. The pulses are just flashing at the time of programming and are not retained.
I have checked the SPI waveforms on DSO. It looks fine.
I am totally clueless as how to go about this problem. In fact I am not getting where is the problem.