Can anyone tell me how a 3rd year ECE student can get an intern in Digital / Analog design ?

It depends upon your interest. I'd only advise, don't opt for a place merely on the basis of its name.
3rd-year b.tech is high time, you must have realized what you are going to do with life, start polishing all the aspects needed to take you there. P.s. work as an intern in a startup if you want to be an entrepreneur, PSU if you want to go for the core. Be very specific in your choice, Cisco/Bharat electronics/cadence if looking for networks or embedded systems, airtel/Vodafone for mobile communication.
All in all, be specific with your approach to find an internship. Among other aspects, this would be the first question when you sit for a job interview later, so mind it.