The lock detect value reported in R110 sometimes reports unlocked even though the PLL is locked.
I have only see this for certain frequencies and when using the reference doubler with a 200 MHz PFD.
I tuned the LMX2595 from 8000 to 15000 MHz (10 MHz steps) and recorded the lock detect value from R110. I did this using 100 and 200 MHz PFDs. For the 100 MHz PFD, I used a fractional denominator of 10. For the 200 MHz PFD, I used a fractional denominator of 20. The plot below shows the results of this test.
Any idea why this happens?
FYI - The MUXout pin always reports lock detect consistent with the PLL being locked.
