4N28W

Overview

The onsemi 4N28W is a single-channel phototransistor output optocoupler housed in a 6-pin DIP package. It provides electrical isolation between input and output circuits with a high isolation voltage rating of 5300Vrms. The device features an infrared-emitting diode coupled to a phototransistor with a base lead for improved switching performance and sensitivity. This component is designed for applications requiring reliable signal transmission across isolated boundaries, offering robust protection against electrical noise and ground loops.

Feature Summary

• High isolation voltage capability of 5300Vrms for safe circuit separation
• Integrated base lead on the phototransistor to enhance switching speed and sensitivity
• Single-channel configuration with standard 6-pin DIP packaging

Applications

• Industrial control systems requiring galvanic isolation
• Signal transmission in noisy electrical environments
• Power supply feedback loops for safety isolation

Procurement Notes

Verify the specific suffix (e.g., W) against the manufacturer's current datasheet to confirm pinout and isolation ratings. Confirm availability status as this part may be subject to discontinuation or lifecycle changes. Ensure the selected variant matches the required package type and isolation specifications for your design.

Selection Notes

Select this component when high isolation voltage and enhanced phototransistor sensitivity are required. The base lead allows for faster turn-off times compared to devices without a base connection. Verify that the 6-pin DIP form factor fits the PCB layout constraints and that the input forward current requirements align with the driving circuit capabilities.

Part Context

The 4N28 series is a well-established family of general-purpose optocouplers from onsemi. The 4N28W variant specifically denotes the version with a base lead on the output transistor, distinguishing it from the standard 4N28 which lacks this feature. This series is commonly used in legacy and modern designs alike for basic isolation tasks.

Replacement Considerations

Check for direct replacements within the 4N28 family or equivalent parts from other manufacturers that offer similar 5300Vrms isolation and 6-pin DIP packages. Ensure any substitute maintains the same pinout and electrical characteristics to avoid redesign.