we make a board with the HMC769 with the same schematic to the hittite board but we have a problem with the HMC769. We think that the HMC769 can communicate with the 121726-2 interface but we have 5v at the output of the charge pump even if we change the frequency of the vco (but the vco stay at 9.47Ghz since the Vtune is same). But when we force up the charge pump, we have 0.9V at the output and the vco go to 8.2Ghz... But when we force down, the charge pump do nothing and stay at 0.9V and the vco stay at 8.2Ghz.
We are new with this vco pll and we don't have a good experience. Do you have a test procedure to understand the problem ?
We are also new in the spi communication...
Thank you to help me.