The 6N139 device consists of an infrared emitting diode, optically coupled to a high gain split Darlington photo detector. It provide extremely high current transfer ratio between input and output, with access to a base terminal to adjust the gain bandwidth. The device is packaged in a 8-pin DIP package and available in wide-lead spacing and SMD options.
High current transfer ratio–2000% typical
High isolation voltage between input and output (Viso=5000 Vrms )