Isocom tlp521 series optoisolators high density mounting isocom tlp521 2 a photoisolator that uses an ir led optically coupled to an npn silicon photo transistor in a space efficient through hole package suitable for applications such as computer terminals industrial systems controllers test and measurement equipment signal transmission isocom tlp521 2 optoisolator 2 channel 50 600 ctr 53kv dil 8