4N27SM

Overview

The 4N27SM is a single-channel transistor output optocoupler manufactured by onsemi. It features a GaAs infrared LED coupled to an NPN silicon phototransistor with an integrated base terminal for enhanced switching speed and sensitivity. The device provides electrical isolation with a DC input isolation voltage of 4170 Vrms. It is housed in a compact 6-pin surface-mount package (SMD-6P). Key electrical parameters include a collector-emitter breakdown voltage of 30V, a maximum forward current of 60mA, and a minimum current transfer ratio of 10%. This component is designed for reliable signal transmission across isolation barriers in various electronic circuits.

Feature Summary

• Integrates an NPN phototransistor with a dedicated base pin to facilitate faster response times and improved control over switching characteristics compared to standard configurations.
• Provides robust galvanic isolation between input and output circuits, ensuring safety and noise immunity in high-voltage environments.
• Utilizes a surface-mount form factor to support automated assembly processes and reduce PCB footprint requirements.

Applications

• Signal isolation in industrial control systems
• Interface circuits for solid-state relays
• Switching power supply feedback loops

Procurement Notes

Verify the specific ordering suffix against the official datasheet to ensure the correct package type and tape/reel configuration. Confirm that the requested quantity matches the manufacturer's standard packaging units. Cross-reference the part number with the latest revision history to ensure compatibility with current design specifications. Check for any regional compliance certifications required for your target market.

Selection Notes

Select this component when a low-cost, general-purpose optocoupler with a base terminal is required for basic isolation tasks. Consider the 30V collector-emitter voltage limit and the 10% minimum CTR to ensure adequate drive capability for the load. Evaluate the thermal performance and isolation voltage rating against the system's operating conditions to guarantee long-term reliability and safety margins.

Part Context

The 4N27SM belongs to the family of transistor-output optocouplers offered by onsemi. It shares functional similarities with other devices in the series but is distinguished by its surface-mount packaging and specific electrical ratings. This variant is part of onsemi's portfolio aimed at providing cost-effective isolation solutions for mass-market electronics applications requiring standard signal transfer capabilities.

Replacement Considerations

Compatible substitutes may include other single-channel transistor output optocouplers with similar isolation voltages and pinout configurations. Verify that alternative parts meet or exceed the 4170 Vrms isolation requirement and the 30V collector-emitter voltage specification. Ensure that the current transfer ratio and switching speed of the replacement device are suitable for the application's timing constraints.