4N37 Optocoupler IC (SOIC 6, Phototransistor Output, Electrical Isolation)

The 4N37 is a general purpose transistor output optocoupler designed to transfer electrical signals between two circuits while maintaining electrical isolation. It consists of an infrared emitting diode and a silicon NPN phototransistor with an accessible base terminal. It is suitable for isolated signal transmission, switching power supply feedback, and industrial control circuits. Verify the exact surface mount package variant before PCB design, as the standard 4N37 is commonly available in a 6 pin DIP package.

Key Features -

• Infrared LED input and NPN phototransistor output

• Electrical isolation between input and output circuits

• Accessible phototransistor base terminal

• High current transfer ratio

• Low input to output coupling capacitance

• Single channel signal isolation

• Suitable for logic signal interfacing and switching applications

Specifications -

• Part Number: 4N37

• IC Type: Transistor Output Optocoupler

• Input Type: Infrared emitting diode

• Output Type: Silicon NPN phototransistor

• Number of Channels: 1

• Package: SOIC 6, verify exact manufacturer variant

• Isolation Test Voltage: Up to 5000V RMS for specified variants

• Collector Emitter Voltage: Refer to the exact manufacturer datasheet

• Current Transfer Ratio: Depends on test conditions and manufacturer variant

• Mounting Type: Surface mount for compatible package variants

Applications -

• Switching power supply feedback circuits

• Microcontroller signal isolation

• Industrial control systems

• Digital logic interfacing

• AC mains detection circuits with appropriate protection

• Relay driver and switching circuits

• Communication equipment requiring electrical isolation