The PS2861B-1 is an optically coupled isolator containing a GaAs light emitting diode and an NPN silicon phototransistor. The package has a shield effect to cut off ambient light, and is mounted in a Shrink SOP (Small Outline Package) for high density applications. Due to the high isolation voltage between the input and output, the PS2861B-1 is suitable for interface and signal transfer circuits that require surface or high-density mounting.