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OP-Amp for HMC439

Question asked by das@1059 on Feb 2, 2018


          i'm using HMC 439 for PLL Application.Right now i'm applying REF Frequency :100 MHz and Varying VCO Frequency for testing purpose to check variation in the Tuned voltage.OP-amp that i'm using is THS4031 but problem i'm facing is that voltage is not varying that much.  I want to generate frequency at 6.9GHz . right now   Frequency getting   between 6.97 GHz to 7 GHz.  Loop filter is design using ADisim PLL please provide me suggestion how set gain of op-amp. and alternate OP-Amp for it. Below i mentioned tuning voltage requirement at 6.9GHz frequency.It is possible to generate 3.05 V? Please provide suggestion. LOOP Filter

PFD:100 MHz

Loop Bw: 10MHz

VCO: HMC 505

Tunning voltage at 6.9 GHZ: 3.05 V