If you're a month-to-month tenant, sure, the landlord is free to raise the rent.
I doubt his notice was proper under state law; most states require a 30-day advance notice. Have no idea what it is in PA, however. I'd contact the local city-county housing authority folks and see if they can point you in the right direction.
That said, do you *really* want him to terminate your tenancy?? I might be inclined to do that if a tenant gave me guff.
Don't see anything specifically about advance notice of rent increase here: