Isocom sfh618 series optoisolators 1 channel low input current 4 pin isocom sfh618a 3xsm an optoisolator utilising an ir led optically coupled to an npn silicon photo transistor a space saving package and low input current makes this photocoupler suitable for applications such as computer terminals industrial system controllers test and measurement equipment signal transmission isocom sfh618a 3xsm optoisolator 1 channel 16 32 ctr 53kv so 4