How to test the phase noise of VCO. VTune access + 5V DC power supply？
For example HMC586
Yes, to test the phase noise, you just need to apply a 5v with an adequate current limit. Then apply a Vtune between 0v and 18v to the Vtune terminal an connect the RFOUT to a suitable phase noise analyzer.
Note that this is open loop phase noise and the closed loop phase noise will be different in-band based on the loop filter, reference frequency etc.