ADF411X PLL IC PD polarity

Phase Detector Polarity Bit
0 Negative
1 Positive

For PD=Positive
Ref/R > RF/N, CP sources current, Vt increases
Ref/R < RF/N, CP sinks current, Vt decreases.


For PD=Neg
RF/N > Ref/R, CP sources current, Vt increases
RF/N < Ref/R, CP sinks current, Vt decreases.




**In project, we use a 3200 mhz reference signal into the "RF" input and an IF signal into the "REF" input. The IF is obtained by mixing down or sampling the VCO frequency.** With a passive or non-inverting active loop filter, PD polarity should be Negative.