The 4N33SD from Fairchild/ON Semiconductor is an Isolator with a Darlington with Base output type. It has an isolation voltage of 5300Vrms and a minimum DC current transfer ratio of 500% @ 10mA.

• Isolation Voltage: 5300Vrms
• Minimum DC Current Transfer Ratio: 500% @ 10mA
• Maximum Output Voltage: 30V
• Channel Output Current: 150mA
• Mounting: 6-SMD
• Switching Turn-On Time: 5μs
• Switching Turn-Off Time: 100μs (Max)
• Forward Voltage: 1.2V
• Vce Saturation (Max): 1V
• Operating Temperature Range: -55°C to 100°C
• Continuous Forward Current-Max: 80mA