Everlight Electronics Co Ltd 4N25S1(TA)-V
Full Technical Specifications
14 Parameters| Parameter / Attribute | Specification / Value |
|---|---|
| Input type | DC |
| Output type | Transistor with Base |
| Mounting | Surface Mount |
| Voltage - isolation | 5000Vrms |
| Voltage - output | 80V |
| Voltage - forward (Vf) | 1.2V |
| Current transfer ratio | 20% @ 10mA |
| Current - DC forward (If) | 60 mA |
| Operating temperature | -55°C~110°C |
| Package | Tape & Reel (TR) |
| Case | 6-SMD, Gull Wing |
| Channels | 1 |
| Vce saturation | 500mV |
| Turn on (Turn off time) | 3µs, 3µs |
Need Stock or a Drop-in Second-Source for 4N25S1(TA)-V?
Package: DIP-6 · Pin-compatible replacements with immediate Shenzhen spot stock
The 4N2x / 4N3x row is the general-purpose opto that predates the PC817 and still fills industrial boards, instruments and old audio gear: a 6-pin DIP with an infrared LED, a phototransistor, and one extra pin the 4-pin generation gave up - the base of the phototransistor, brought out for speed-up tricks and threshold trimming. The family is a CTR ladder wearing four part numbers: 4N25/26 at 20% minimum, 4N27/28 at 10%, and the 4N35/36/37 trio at 100% - one of the highest CTRs of any general-purpose opto, which is why it survives in circuits that need gain more than speed. Substituting within the row is honest work; substituting against the 4-pin PC817 row is the classic socket error.
Verified Pin-Compatible Replacements (4 verified alternatives)
The 20% Rung - Same Socket, Real Numbers
Shenzhen Spot Stock (24-48h Dispatch)
The 20% minimum CTR member at 10mA LED current (same bin as the 4N26): the everyday grade of the row, pin-identical to every 4N2x and 4N3x part.
Standard 6-pin opto envelope: 5.3kV-class isolation in the classic parts, 30V-class collector-emitter ratings, pin 6 base exposed.
The 100% CTR Rung
Shenzhen Spot Stock (24-48h Dispatch)
The high-gain member of the row: 100% minimum CTR at 10mA (40% guaranteed across the full temperature range), the reason it appears wherever the driving current must stay small.
Same envelope; isolation figure per the vendor grade (5.3kV class in the classic datasheets).
The Ancestor Row
Shenzhen Spot Stock (24-48h Dispatch)
The 6-pin row the 4N parts were defined alongside: H11A1 at 50% minimum CTR, H11A5 at 30% - same socket and base pin, its own gain ladder.
Same envelope and isolation class.
The 4-Pin Cousin - Different Socket
Shenzhen Spot Stock (24-48h Dispatch)
The 4-pin general-purpose opto of the next generation: same phototransistor idea without the base pin, and its own CTR rank system (A/B/C/D) that replaced the 4N CTR ladder in new designs.
Same functional envelope; 5kV-class isolation in the modern parts.
Buyer & Quality Checklist for Sourcing Alternatives
- The CTR minimum is the specification: 4N25/4N26 = 20%, 4N27/4N28 = 10%, 4N35/4N36/4N37 = 100% (40% across the extended range). The 4N3x trio is the same sockets at five times the gain - the direction of every substitution follows this number.
- Pin 6 (base) distinguishes this row from the 4-pin generation: a base-emitter resistor speeds the transistor up (trading gain for bandwidth), and a small bias trims the threshold. Designs that used it detect a replacement without it immediately - noise and edge behavior change.
- The 4-pin PC817 row is not the same socket: no base pin, a different rank system (A-D), and a modern isolation class. Functionally comparable in many circuits, mechanically incompatible without an adapter.
- LED drive is part of the gain budget: the CTR numbers assume 10mA of LED current. A circuit that halved its LED drive for efficiency cannot expect the original switching thresholds from the same grade.
- The classic 6-pin bodies carry 5.3kV-class isolation figures - verify per vendor and grade; clone rows trade here first.
- For repair of old gear, read the service manual part against the row: the H11A names and the 4N names cross freely in tables, and the CTR number is the only thing that transfers between them.
Frequently Asked Technical Questions
Q: What is the difference between 4N25 and 4N35?
A: Current transfer ratio: 4N25 is 20% minimum, 4N35 is 100% minimum (40% guaranteed over the extended temperature range). Same 6-pin socket and pinout; the 4N3x part is the high-gain version of the same design.
Q: What is pin 6 on a 4N35 used for?
A: The phototransistor base, brought out for design freedom: a base-emitter resistor speeds up switching, a small bias trims the effective threshold. It is also the physical difference from the 4-pin opto generation.
Q: Can I replace a 4N35 with a PC817?
A: Functionally similar in many circuits, but not socket-compatible - the PC817 is a 4-pin part without the base pin. Fitting one needs an adapter or a new layout, and the base-pin behavior is lost either way.