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Im not getting the programmed frequency out of HMC767

Question asked by fredrik.gulbrandsen on Jun 19, 2017
Latest reply on Jun 30, 2017 by fredrik.gulbrandsen

Hello,

 

I have trouble using the HMC767. I have built my own circuit based on the evaluation board (see attached file) but I cant get it to work. It wont lock to the programmed frequency which is 9025 MHz. Instead I measure a frequency between 9.9-10 GHz. When I measure the charge pump pin and Vtune pin I get approximately 150 mV and 14 V respectively.  I measure a 50 MHz 2.6 Vpp sinusoidal reference.

 

I have tried to program the registers in many different ways but nothing seems to work. In the last attempt I used an example found here (see attached file), but it did not help. I think I have programmed the unit because I can read back from the registers the same values I put in.

 

What could be the problem? Any help would be much appreciated.

 

Best regards

Fredrik Gulbrandsen

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