Is there an IBIS model for the ADG726?
If you have any, I would appreciate it if you could share it.
Unfortunately, there is no ADG726 IBIS model available on the Analog.com ADG726 product webpage.
Within the SMX group we are actively developing new LTspice models, it is possible to put in a request to have an ADG726 LTspice model developed and released on the LTspice library, if you would like ?
Firstly, the ADG726 LTspice model will need to be approved by the LTspice modelling team.
Once that is completed, it should take ~1-2 weeks to develop the model and then it should be ready for release.
The ADG732 and ADG726 LTspice models are of different configurations, but the performance specifications are the same for common voltage supplies and temperature ranges etc.
So it is possible to use the IBIS model as a rough check of the performance of the ADG726/ADG732 Multiplexer, but they are not the exact same multiplexer as you have stated in your question.