4N22

Overview

The 4N22 is a single-channel transistor output optocoupler manufactured by TT Electronics/Optek Technology. It features an NPN phototransistor output and utilizes a TO-78-6 metal can package for through-hole mounting. The device provides electrical isolation with a rated insulation voltage of 1000 Vrms. Key electrical parameters include a maximum collector-emitter voltage of 35 V, a maximum collector current of 50 mA, and a minimum current transfer ratio of 25% at a forward current of 10 mA. The typical rise and fall times are both 15 µs. It operates within a temperature range of -55°C to +125°C.

Feature Summary

• Provides galvanic isolation between input and output circuits using an internal LED and phototransistor pair.
• Features an NPN phototransistor output with a base terminal accessible via the package leads.
• Constructed in a hermetically sealed TO-78-6 metal can package suitable for high-reliability applications.

Applications

• Industrial control systems requiring signal isolation
• Computer logic interfacing for data transmission
• Power supply feedback loops

Procurement Notes

Verify component authenticity against official manufacturer documentation before integration. Confirm that the specific lot matches the required RoHS status and lead finish specifications. Ensure the TO-78-6 package dimensions align with the target PCB layout. Validate thermal performance under maximum operating conditions to maintain reliability within the specified temperature range.

Selection Notes

Select this component when a robust, hermetically sealed isolation solution is required for moderate-speed digital signals. The TO-78-6 package offers superior environmental protection compared to plastic variants. Consider the 15 µs switching speed for application timing constraints. Verify that the 35 V collector-emitter voltage rating accommodates the load requirements without exceeding limits.

Part Context

The 4N22 belongs to the standard family of transistor-output optocouplers produced by Optek/TT Electronics. It shares functional similarities with other models in the series but is distinguished by its specific metal can packaging and hermetic sealing properties. This form factor is often preferred in aerospace or military-grade designs where environmental durability is critical.

Replacement Considerations

Public confirmed substitute part numbers: 4N22A, 4N22ATXV, 4N22ATX.