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HMC394LP4 not enough information on data sheet.

Question asked by Alexittp on Nov 3, 2017
Latest reply on Nov 27, 2017 by MRichardson

On page 4-2 of the attached HMC394 data sheet, v09.0114, AD provides a plot : "OUTPUT POWER, 5 MAJOR DIVIDE RATIO STATES, T=25°C"


the output power is given in dBm from N=2 to N=32.


In my setup, I will inject a SQUARE wave of Fin=3.1805 MHz and 9 dBm max, with N=32 (Ai=1) to obtain Fout=99.392kHz.



Q1 : what is the input power used for this plot ? is it 10 dBm ?


Although we cannot change it, could you please explain in simple words why the output power is decreasing as a function of N ?



Q2 : Do you confirm that the HMC394 is able to handle the low frequency of 3.1805 MHz ?


If well understood, the answer should be "yes", according to the note (1) page 4-1 : "Divider will operate down to DC for square-wave input signal".


Am I correct ?


But, according to the plot "Input Sensitivity Ratio States", page 4-2, there is a "RECOMMENDED OPERATING WINDOW", starting at 250MHz.


Or, is this plot for sinewave only ?



Q3 : In my setup, I can feed the HMC394 with a LVDS signal, but the EVAL board only comes with a single ended input : do you know WHY AD made this choice ?


What is strange is that there is no possibility to select the input mode, LVDS or Single Ended, offered on the EVAL board.


If I would like to design a new PCB myself, do you confirm I can work in LVDS mode ?



Q4 : What should I do with the /OUT signal if I only need the OUT signal ? Should I load it with a 50 Ohms ?