Stability analysis

@rathi
I used many versions of SPICE simulation, including PSPICE. ALTIUM SPICE and LTSPICE. All of them are built on the same Berkley SPICE and only user interface is different. PSPICE was the best of them, when it was still available. I used (Windows) LTSPICE to simulate power supply circuits, mostly Linear Technology switching power supply ICs. You need good knowledge of electronics, plus a lot of patience and even then it can be very frustrating. Program might not converge for no reason, not to mention that program itself is buggy, especially Mac version, that I have installed on my computer. It runs now, but was hanging up constantly before last update. You need to find and follow tutorial on LTSPICE like this one:
http://denethor.wlu.ca/ltspice/

Install LTSPICE (it is free) and follow tutorial step by step. There might be other tutorials made by different universities.  Also look at the links to references at the bottom of this tutorial.

rathi, I think you might want to ask that question under Tech Talk. LTSPICE is a circuit simulator. I suspect you would use it to analyze the AC performance of a given circuit layout using specific parts. This is not a site for electronics engineers although there may be a few here. Most of us including myself have no idea what to do with that program.