Due to the obsolescence of part HMC704 we have replaced this PLL by ADF41513. In one of the designs we were using this solution, we had a passive loop filter with a VCO with a Vtune from 0.5 to 4.5 V. Now, with ADF41513 we can not lock the VCOs that have a Vtune greater than 2.8 V (around). Is it any possiblity of increasing the output Vtune of the PLL (apart from placing an active loop filter) using the ADF41513? In datasheet it is stated that Vp is 3.3 V +/- 5%.
Thanks and best regards,