4N27

Overview

The Texas Instruments 4N27 is a single-channel transistor output optocoupler housed in a PDIP-6 package. It provides 5000 Vrms isolation voltage between input and output. The device features an NPN phototransistor output with a minimum current transfer ratio of 10%. Key electrical parameters include a maximum collector-emitter voltage of 80 V, a forward current rating of 60 mA, and a forward voltage of 1.5 V. The component supports through-hole mounting and operates within a temperature range of -55°C to +110°C.

Feature Summary

• Provides high-voltage electrical isolation between input and output circuits
• Compatible with standard TTL integrated circuit logic levels
• Features a compact dual-in-line package for through-hole mounting

Applications

• Feedback isolation in switching regulator designs
• General-purpose signal isolation in industrial control systems
• Microcontroller interface circuits requiring galvanic separation

Procurement Notes

Verify the specific manufacturer source, as the 4N27 is produced by multiple vendors including Everlight and Texas Instruments. Confirm RoHS compliance status and lead times, as availability varies significantly across suppliers. Ensure the selected variant matches the required isolation voltage and package type specifications for your design.

Selection Notes

Select this component when a low-cost, general-purpose optocoupler with moderate speed is required. Verify that the 10% minimum CTR meets the drive requirements of the receiving circuit. Consider the 3 µs rise/fall time limitations for high-frequency applications where faster alternatives may be necessary.

Part Context

The 4N27 belongs to the widely used 4N2x series of transistor output optocouplers. This family is characterized by its compatibility with standard logic families and robust isolation capabilities. It serves as a foundational component for basic digital signal transmission across isolated boundaries in various electronic assemblies.

Replacement Considerations

Direct pin-compatible substitutes include the 4N25, 4N26, and 4N28 from the same series. Other manufacturers offer equivalent parts such as the PC123 or ILD200, though parameter verification is essential.