Vishay, SFH615A-3X018T Phototransistor Output Optocoupler, Surface Mount, 4-Pin SMD

The Vishay optocoupler feature a variety of transfer ratios, low coupling capacitance and high isolation voltage. These couplers have a GaAs infrared diode emitter, which is optically coupled to a silicon planar phototransistor detector and is incorporated in a plastic SMD package. The coupling devices are designed for signal transmission between two electrically separated circuits.

Excellent CTR linearity depending on forward current
Fast switching times
Low CTR degradation
Low coupling capacitance