There are several resources of example circuits for LTspice IV. There is a directory typically installed at C:\Program Files\LTC\LTspiceIV\examples\Educational that gives numbers non-commercial examples of SPICE simulations that illustrate different analysis types, methods or program features. In the directory C:\Program Files\LTC\ LTspiceIV \examples\jigs there is an example simulation for every Linear Technology device with a macromodel in LTspice IV. Note that these jig circuits are often only test jigs for the macromodel, not necessarily recommended reference designs. Most importantly, your Linear Technology office can probably give you design support specific for your application needs.