first they take a prelims which is quite easy then mains which is tough then they will call you for interview and interview will be based on the basic RL/RC RLC circuits and op-Amps and VLSI basics

It will be around of 1 to 3 hours...For me it took 3 hours ... i was allowed to seated in a computer lab in ANITS college...only for people selected for analog interview.they will make us to sit four corners of same room. and ask us to solve some random 2nd round (mains) questions.Genenraly most of them are related to analog ic design...a btech person cant have much knowledge...so they ask easy questions and help us to solve unsolved questions...prepare c language & digital also and aptitude well