When is a good age to introduce my newborn to our family dog?

since day 1 discharge from hospital. initially dog will be super scare of bb cries... After a while used to it. and when bb sleeps, dog also sleeps nearby like protecting. though now elder boy about 21 mths also smack my 2.5 kg dog.. but they still like to play chase together. now my dog will sleep near youngest boy of 1.5 mth... the boys are used to my dog once in a while bark.