ATP + L-phenylalanine + tRNA(Phe) = AMP + diphosphate + H(+) + L-phenylalanyl-tRNA(Phe) Binds 2 magnesium ions per tetramer. Optimum temperature is 95 degrees Celsius. Tetramer of two alpha and two beta subunits. Belongs to the class-II aminoacyl-tRNA synthetase family. Phe-tRNA synthetase alpha subunit type 2 subfamily.