Can I move out before 90 days as soon as I find a new place?

I received a 90 day vacate letter from my landlord who wants to move back in. The letter was dated Nov. 5, thus 90 days would be Feb. 5. The letter also said or no later than Feb. 28 which is the date my lease is up. What is the earliest I can move out without penalty of losing my security deposit or not being responsible for paying rent?