PLL IC and 1-16 V tuning VCO

Using a simple voltage divider (2 resistors) reduce the voltage from 1-16V to 0.3-5V and feed it to the 5V PLL ..
Regards,
IanP

Phase discriminator output of the PLL IC has to be amplified. It can be done by active loop filter.

The VCO operates at 12V supply. How can I choose an op-amp that can give me 16V output with 12V supply?

You need an amplifier not a divider.
Try this simple circuit that will give you at the output a swing between 0V and 16V, for 0V to 5V at the input (you need a 16V supply on the board).
Beware that the resistor values are not optimized, and probably you have to play a little bit with them.