What loop filter design tool should I use for LTC694x PLLs and PLL/VCOs?
The short answer is:
LTC6945, LTC6946: Either PLLWizard or ADIsimPLL
LTC6947, LTC6948: Either FracNWizard or ADIsimPLL
The long answer is:
Since 2002 ADI has used ADIsimPLL for loop filter design and simulation for the full catalog of PLLs, VCOs, and PLL/VCOs. When ADI acquired Linear Tech in 2017, Linear Tech had four released PLL/VCO parts that used Linear Tech developed loop filter design and simulation tools (PLLWizard and FracNWizard). Since these Linear Tech tools also functioned as the software GUI to control the evaluation hardware, these tools are still supported. The LTC6948 was added to ADIsimPLL, as of September 2018. The LTC6945, LTC6946, and LTC6947 were added to ADIsimPLL, as of August 2021. One nice feature ADIsimPLL has, that was missing in the Linear Tech tools, is time domain simulation for loop settling times.
And for those people who, like me, just love spreadsheets… here is a quick comparison