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Problems with the HMC1032

Question asked by bene on May 13, 2015
Latest reply on May 21, 2015 by bene

Hi,

 

I'm having troubles to properly configure the HMC1032 for my purposes. Does anybody else uses this device?

 

I need a differential clock signal from 140MHz - 210MHz and I thought this device is perfect for me. I have a board similar to the evaluation board but I cannot properly set the device up.

 

My problems in short:

I communicate with a microcontroller. This communication works fine, I can read back the ID and most of the registers properly.

The first question: what is the VCO quiescent frequency? I need it to properly set the N-divider. I didn't find anything in the datasheets. From my trail and error method I think its around 4.2GHz. Is that right?

I have a reference at 10MHz in I could set the reference divider properly. I investigatet it by setting the R-div output to the GPO pin and it looked as expected. I did the same with the VCO divider output, this is how I came to the assumtion of 4.2GHz frequency (5MHz output at N=840)

however. the PLL apparently does not lock. I tried to read out Reg10h (VCO Tune Register) but here I think the values are not ok. I also tried to disable the autocalibration feature and set some values for the capbank but this did not change anything. In my desperation I also unconnected the loop filter and just set known dc-voltage to the vtune but the oscillation frequency (N-div-output at GPO) did not change.

 

Can anybody help me. If you need further informations, just ask.

 

thanks in advance!!!

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