AnsweredAssumed Answered

How to enable the RF Divide by 2 of the HMC704

Question asked by tfish on Sep 22, 2017
Latest reply on Sep 25, 2017 by dyoung1

I am using the HMC704 to phase lock a VCO with to an output frequency of 4200MHz. I have enabled the RF divide by two (or I think I have) by setting Reg08[19] = 1. However when I monitor the VCO divider output via the GPO pin and Reg0F[0:4] = 10 I see a signal with a frequeny of about 104MHz. This is two times what I would expect to see. I have tried setting Reg08[19] = 0 (thinking the documented logic might be incorrect) and get the same result. Is there something else that needs to be set inorder to enable the RF divide by two?

 

My configuration parameters are:

Xtal Freq: 260MHz
Rdivider: 5
Fpfd: = 52MHz (I have viewed this signal on the GPO output as well, Reg0F[0:4] = 9, and it is the correct frequency)

 

RF input: 4200MHz
intg = 40
frac = 6452775

 

Thanks!

Outcomes