4N39 Optically Coupled SCR - Technical Summary

Overview

The 4N39 is an optically coupled Silicon Controlled Rectifier (SCR) that integrates a Gallium Arsenide (GaAs) infrared emitter and a silicon photo SCR sensor in a single package. This component is designed to provide reliable switching and isolation in various electronic applications. The 4N39 is particularly suited for scenarios where electrical isolation between control and load circuits is critical, such as in industrial automation, power control systems, and safety-critical applications.

The device offers solid-state reliability, high isolation voltage, and efficient switching performance. Its standard Dual In-line Package (DIP) makes it easy to integrate into existing circuit designs while maintaining compatibility with automated assembly processes.

Features

• Low Turn-On Current: Typical forward trigger current (I_FT) of 5.0 mA enables efficient switching.
• Gate Trigger Current: 20 mA gate trigger current (I_GT) ensures reliable SCR activation.
• High Surge Current Handling: Capable of handling surge anode currents up to 10 A.
• High Blocking Voltage: Supports blocking voltages up to 200 VAC peak.
• Low Gate Trigger Voltage: Gate trigger voltage (V_GT) of just 0.6 V for efficient control.
• Excellent Isolation: Provides high isolation voltage of 5300 VAC RMS, ensuring safety in high-voltage applications.
• Solid-State Reliability: No moving parts, ensuring long-term durability and consistent performance.
• Standard DIP Package: Easy to integrate into PCB designs with a standard dual in-line package.
• Safety Certified: Underwriters Laboratories (UL) recognized under file #E52744.

Applications

The 4N39 is widely used in applications requiring electrical isolation and reliable switching. Common use cases include:

• Industrial Control Systems: Used for switching high-voltage loads in PLCs and motor control circuits.
• Power Supply Control: Provides isolated switching in AC/DC power supplies and inverters.
• Medical Equipment: Ensures safe isolation in patient-connected devices.
• Telecommunications: Used in line interface circuits and surge protection modules.
• Home Appliances: Provides reliable switching in washing machines, refrigerators, and HVAC systems.
• Lighting Control: Enables dimming and switching in high-voltage lighting systems.

Electrical Characteristics

Absolute Maximum Ratings

• Forward Current (I_F): 60 mA (continuous)
• Reverse Voltage (V_R): 3 V
• Surge Anode Current (I_TSM): 10 A (non-repetitive)
• Blocking Voltage (V_DRM/V_RRM): 200 V (peak)
• Isolation Voltage (V_ISO): 5300 VAC RMS
• Operating Temperature Range: -55°C to +100°C
• Storage Temperature Range: -55°C to +125°C

Optical Characteristics

• Forward Voltage (V_F): 1.2 V (typical) at I_F = 10 mA
• Turn-On Current (I_FT): 5.0 mA (typical)
• Gate Trigger Current (I_GT): 20 mA (maximum)
• Gate Trigger Voltage (V_GT): 0.6 V (maximum)

Switching Characteristics

• Turn-On Time (t_on): 10 µs (typical)
• Turn-Off Time (t_off): 50 µs (typical)
• Critical Rate of Rise of Off-State Voltage (dv/dt): 10 V/µs (minimum)

Package Information

The 4N39 is available in a standard 6-pin Dual In-line Package (DIP) with the following dimensions:

• Package Type: DIP-6
• Length: 9.65 mm (max)
• Width: 6.35 mm (max)
• Height: 3.81 mm (max)
• Lead Pitch: 2.54 mm
• Lead Material: Tin-plated copper alloy
• Mounting Style: Through-hole

Pin Configuration

• Pin 1: Anode (LED)
• Pin 2: Cathode (LED)
• Pin 3: No Connection (NC)
• Pin 4: Anode (SCR)
• Pin 5: Cathode (SCR)
• Pin 6: Gate (SCR)

Reliability and Safety

The 4N39 meets stringent reliability and safety standards, making it suitable for critical applications:

• UL Recognition: Certified under Underwriters Laboratories file #E52744.
• Isolation Test Voltage: 5300 VAC RMS for 1 minute between input and output.
• Flammability Rating: UL94 V-0 compliant for plastic material.
• Moisture Sensitivity Level (MSL): MSL 1 (unlimited floor life at ≤30°C/85% RH).

Conclusion

The 4N39 optically coupled SCR is a robust and reliable component designed for applications requiring electrical isolation and efficient switching. With its high blocking voltage, excellent isolation characteristics, and solid-state reliability, it is well-suited for industrial, medical, and consumer electronics applications. The standard DIP package ensures easy integration, while its UL certification provides assurance of safety and performance compliance.