ADF4360-7_output impedance-2

Question In ADF4360-7's datasheet, it says: "Experiments have shown that the circuit shown in Figure 30 provides an excellent match to 50 Ω over a limited operating range of the ADF4360-7 (850 MHz to 950 MHz). " Here the value of the inductor is 7.5 nH. But in the "ADF4360 impedance match.xls ", When the frequency is 0.8GHz~0.9GHz, the Inductor value is about 40~50. So I am not sure which inductor should should be the series L, is it the 47nH or 7.5 nH in the Figure 30? Answer In the table, the R and X value shows the idea impedance due to frequency. The Series L column just shows if you want to tune the X to 0, the series inductor's value that you need to add. (It is NOT means the shunt L 47nH) But in real case, the bond wire and PCB parasitic capacitance will change the output impedance, the final impedance before the inductor may become totally different. For example, Z0=63-j240, if PCB parasitic capacitance equal to shunt 1pF, the final impedance is about 10-j100. So experiments are very important here, as we have no way to accurate count all the factors.

ADF4360-7: ADIsimPLL gets small L value

Question I have a question about ADIsimPLL for simulating ADF4360-7. When I am setting the output as a fixed frequency of 818.4MHz, PFD=2.5575, the external inductor L1=L2=611pH. But we can not get such parameters according to the equation or figure 24 on page 22 of datasheet. It seems L1, L2 should be at least higher than 1nH. Would you advise please? Answer 611pH is hard to implement in real coil inductors, but the ADIsimPLL software could still calculate the value. The problem is because you select the div/2 output which means the VCO is actually run @1.6GHz. You can change the VCO frequency to 818.4MHz and this will result in a higher inductor value( see picture).

ADF4360-7_VCO Open Loop Phase Noise Test

Question I am using ADF4360-7. Here the VCO Phase-Noise is measured in Open-loop conditions. How do I configure the EVB as open-loop? Answer Open loop test need to program CP to 3-state and apply a very clean voltage reference on Vtune (such as DAC output).