I am trying to use LT Spice to model a mixed digital and analog circuit. I have Spice models for most components, and I can make my own for stuff like obscure germanium zener diodes using spec sheets to parameterize standard models, but I find myself stuck on more complex subcircuits.

I am using a Fairchild FAN7371 hi-side driver (but I could switch to a FAN73711) and have asked Fairchild for a LTSpice model. They apparently supply these only to big customers, not hobby guys. I got a Bspice model (not encrypted) and can use it in LTspice except it depends on other Bspice models I do not have.

So who has the models for such things? I will need to choose and model a low-side driver and some opto-isolator chips that also seem to be hard targets for finding the Spice models.

Thanks for any help.

 

Unfortunately a lot of ICs don't have Spice models so it's sort of hit and miss as to whether you can find one.
Typically I just do a Google search for the part number with "spice model" as a suffix.