I put the AD8302 on a board of my own design. I purchased an AD8302 eval board that will be coming soon.
I am getting at the VPHS output a 5MHz signal of the same frequency as the 5MHz I apply to both inputs. I like some help. What is the normal operation of the phase detector XOR circuitry and filtering settings??
I made a test with a 5 MHz -30dB generator going to a splitter. On one side, I put a very long cable to get a phase difference. I made the PCB with a low pass1k 4700pF RC filter to get 33kHz BW. In my final application, I will have the phases difference changing in time with a BW below 24kHz. Just for now, I keep the phase difference constant.
I made a capture below with the blue channel at VPHS and the yellow after R6 C9. I get 1.47Vpp at VPHS and 12mVpp after the low pass filter. I did not use C8 at PFLT. Was the usage of C8 the main idea to convert the digital XOR output into an analog value? Is the circled X in the below drawing the XOR?
So with the formula at page 16, do I just use T (ns) = 3.3 × CAVE (pF). where I put T my time constant for 1/24kHz = 41000ns ?