Hi,
Pardon me to rant but this is a very frustrating experience using the HMC440 evaluation module. I have acquired this part for more than a year and had been off/on this project of trying to build an oscillator and till now, no success just because the HMC440 will not just work. After several tests and scouring through this forum, I have now come to the conclusion that the module I have is broken. And sadly at no time could I get it to work as described in its datasheet and that of similar parts.
At the time when it seems to work, the outputs at NU/ND were way below specified levels. In fact, I was could only measure the frequency of REF, and not the frequency/phase difference between REF and CLK. See image below of my scope where NU was barely 560mVpp/100MHz as opposed to 2000mVpp as specified in the datasheet.
Currently, I do not have any chirps on either NU/ND/NFOUT/FOUT. Only measurement on my scope are NU and ND at 5V on startup and ND changing to 3V only when input level at CLK/VCO is as high as 8dBm while ND remains at 5V. Please refer to images below.
To setup the test measurements, I have followed the examples/suggestions in:
HMC440 - Problem at low frequencies - Q&A - RF and Microwave - EngineerZone (analog.com)
And also tried to replicate the test data of HMC4069 presented in its datasheet. I'd expected similar result (except for the LD which is not available in the HMC440).
I also noticed that while supplying the eval module with 5V, the voltages at the A0-A4 divider programming do not seem to be at correct values. When the jumper is pulled out (i.e. state 1), I expected to measure 5V (as per the datasheet) but here I could only detect 3V. And when the jumper is put in place (i.e. state 0), measured value was 0V. It is unclear to me why jumper pull out state of 1 is not reaching 5V.
I will be shopping around for a replacement synthesizer. Kindly suggest a synthesizer that is 'compatible' with the HMC6380 VCO, that can take in CLK of 150-960MHz, REF of 25 to 160MHz at divider of 6. The proposed part needs to be more rugged than the current HMC440, more recent, and evaluation module is readily available, with model available in ADISimPLL.
Thanks!
Title changed by original poster
[edited by: obabarin at 10:11 AM (GMT -4) on 16 Sep 2024]