I have been using the HMC767 evaluation board for a few weeks controlling it from our own DSP. Then we noticed that the frequency was not what we expected and we decided to troubleshoot it using the Hittite evaluation software. We realized that the evaluation software showed a "Lost Communication" message. We used the same Hittite USB Interface to control a different HMC767 evaluation board and this time it was working OK, which means that the Software + USB Interface combo is working fine. We then started troubleshooting the messages sent by the USB interface to the Evaluation Board and noticed that there is a difference between the working HMC767 and the bad HMC767 (please see attached). Also, please note that we measured all voltages and currents and they are the same between the two boards.
Can anybody help me fix this issue? Or at least understand why this is happening?