Currently, I have purchased, ADF4108 Eval-Board (EV-ADF4108EB1Z b). I am trying to run the same configuration what stated in the Eval-Board datasheet before connecting external LF and VCO in-order to get familiar with the eval borad Kit. The specifications are given below for the Loop Bandwidth of 15KHz (as per the datasheet):
VCO frequency=6400 MHz
Reference Frequency: 40 MHz
PFD Frequency: 2500 KHz.
CP-1 and 2: 5mA
PD Polarity: Negative
On powering ON and proving the commands form the AD Int-N software as mentioned above, I can able to see the carrier at the desired frequency.
I am using 40 MHz Sine Wave TCXO AST3TQ-40 MHz for my REFIN.
I am facing the following issues:
1. The Lock Detect LED D1 is not turned ON. Does it means, PLL is not Locked?
2. IF so, why the PLL is not locking as I have not done any changes on the board except the 40 MHz Sine wave TCXO?
3. On placing Oscilloscope probe on MUXOUT Test port keeping the MUXOUT to Digital lock, I am getting the 500mV on the scope. What does it imply?
4. What are the other alternatives to check the whether the PLL is locked or not?
I shall be very thankful for your support.