AA - is an absolute No-No for putting your good money. Don't go by what the official explanation of the rating says...It is quite risky.
Please go for only AAA-rated corporate FDs and nothing else. We, at first don't even look at anything below AAA. Remember DHFL and IL&FS were AAA rated when they went down.
In India, AAA are a dime a dozen...In fact even this highest rating is some sort of a joke in India.
You'd be surprised to know that, in spite of hosting some of the world's best and financially solid companies, in USA, only two companies have a AAA rating - Microsoft and Johnson&Johnson. Even Apple hasn't been given AAA by all the rating agencies !!