Alternatives to onsemi 4N27
onsemi 4N27 and its qualified second sources, compared on form/fit/function, stock, lifecycle and price — the same checks Parter runs inside a BOM.
| 4N27onsemi |  4N27Vishay Semiconductors |  4N25Vishay Semiconductors | +4more | |
|---|---|---|---|---|
| FFF Compatibility | Shares the identical standard DIP-6 package and pinout layout.Identical physical package dimensions and mounting footprint.Matches or exceeds all original electrical specifications, including isolation voltage and CTR. | Shares the identical standard DIP-6 package and pinout layout.Identical physical package dimensions and mounting footprint.Matches or exceeds original specs, providing a performance upgrade with higher CTR. | ||
 AI Summary | 4N27 by onsemi: Optoisolator Transistor with Base Output 5000Vrms 1 Channel 6-DIP. | The Vishay 4N27 is a direct drop-in replacement for the obsolete Texas Instruments part. It fully matches the original JEDEC-standard 6-DIP pinout, 10% minimum current transfer ratio (CTR), and 5000 Vrms isolation rating. This ensures seamless operation in existing designs without circuit modifications.
| The Vishay 4N25 is a closely related sibling from the same active family. It provides a performance upgrade by guaranteeing a minimum CTR of 20% (compared to 10% on the 4N27) while maintaining the exact same DIP-6 physical package, 5000 Vrms isolation, and pinout assignments. This is an excellent alternative for circuits requiring stronger signal coupling.
| |
| Lifecycle Status | Obsolete | Active | Active | |
| Market Availability | In stock | In stock | In stock | |
| REACH | REACH | REACH | REACH | |
| RoHS | RoHS | RoHS | RoHS | |
| Description | Optoisolator Transistor with Base Output 5000Vrms 1 Channel 6-DIP | Optoisolator Transistor with Base Output 5000Vrms 1 Channel 6-DIP | Optoisolator Transistor with Base Output 5000Vrms 1 Channel 6-DIP | |
| Manufacturer | onsemi | Vishay Semiconductors | Vishay Semiconductors | |
| Type | Optocouplers, Optoisolators | Optocouplers, Optoisolators | Optocouplers, Optoisolators | |
| Datasheet | Open | Open | Open | |
| Lead Time | 7 days | 18 weeks | 18 weeks | |
| Country of Origin | - | - | - | |
| Export Control Class Number | EAR99 | EAR99 | EAR99 | |
| HTSUS Code | 8541.49.8000 | - | - | |
| Moisture Sensitivity Level | 1 (Unlimited) | - | - | |
| Input Type | DC | - | - | |
| Output Type | Transistor with Base | - | - | |
| Mounting Type | Through Hole | - | - | |
| Package / Case | 6-DIP (0.300", 7.62mm) | - | - | |
| Number of Channels | 1 | - | - | |
| Voltage - Isolation | 5000Vrms | - | - | |
| Vce Saturation (Max) | 500mV | - | - | |
| Operating Temperature | -55°C ~ 100°C | - | - |
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Related parts
| Part | Market availability | Lifecycle | Alternatives available |
|---|---|---|---|
 4N26Sonsemi | Discontinued | Obsolete | 4Alternatives availableSee Alternatives |
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Frequently asked questions
Yes. The onsemi 4N27 is marked obsolete, so the manufacturer has discontinued it and any remaining supply is limited to distributor stock. The qualified second sources on this page are active parts you can design in today.
The closest qualified second sources for the onsemi 4N27 are the 4N27 (Vishay Semiconductors) and the 4N25 (Vishay Semiconductors), out of 6 matched alternatives in total. Each is compared against the original on fit, form and function in the table above.
Not always. The alternatives to the 4N27 are matched on function but can differ in package, pinout or a key parameter, so review the fit/form/function notes in the table and the datasheet before designing one in.
The 4N27 (onsemi) is a part in the Optocouplers, Optoisolators category. This page lists qualified, cross-referenced replacements for it with a side-by-side comparison.
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