BUY SFH617G-2 https://www.utsource.net/itm/p/563717.html
LOW INPUT CURRENT PHOTOTRANSISTOR OPTICALLY COUPLED ISOLATORS
Description: SFH617G-2 is a 4-pin DIP phototransistor optocoupler manufactured by Siemens. Features: High current transfer ratio High isolation voltage Low input current Low output saturation voltage High speed switching Low power consumption Applications: Signal transmission between two circuits with different potentials Isolation of digital and analog signals Switching and control applications High speed logic interfacing Motor control (For reference only)