# 4N37

**Vishay Intertech** · Optocouplers - Phototransistor Output · DIP-6

4N37 from Vishay Intertech, in a DIP-6. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | A | passive | Anode of the infrared LED input, with forward current rated at 50 mA maximum and reverse voltage 6 V maximum. |
| 2 | C | passive | Cathode of the infrared LED input; 1 A surge current (t ≤ 10 µs) and 70 mW input power dissipation maximum. |
| 3 | NC | unconnected | No internal connection. |
| 4 | E | passive | Emitter of the NPN phototransistor output; emitter-base breakdown voltage is 7 V. |
| 5 | C | passive | Collector of the NPN phototransistor output, rated VCEO 70 V and IC 50 mA maximum (100 mA for t ≤ 1 ms). |
| 6 | B | passive | Base of the NPN phototransistor, brought out for the base connection. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Vishay Intertech |
| Package | DIP-6 |
| Category | Optocoupler/LED/Digital Tube/Photoelectric Device |
| Pins | 6 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Collector emitter breakdown voltage | BVCEO | 30 |  |  | V | IC = 1 mA | 2 |
| Emitter collector breakdown voltage | BVECO | 7 |  |  | V | IE = 100 μA | 2 |
| Collector base breakdown voltage | BVCBO | 70 |  |  | V | IC = 100 μA, IB = 1 μA | 2 |
| Forward voltage | VF |  | 1.3 | 1.5 | V | IF = 10 mA | 2 |
| Forward voltage at low temperature | VF |  | 0.9 | 1.7 | V | IF = 10 mA, Tamb = - 55 °C | 2 |
| Reverse current | IR |  | 0.1 | 10 | μA | VR = 6 V | 2 |
| Collector emitter leakage current | ICEO |  | 5 | 50 | nA | VCE = 10 V, IF = 0 | 2 |
| Collector emitter leakage current | ICEO |  |  | 500 | μA | VCE = 30 V, IF = 0, Tamb = 100 °C | 2 |
| Resistance, input output | RIO | 1011 |  |  | Ω | VIO = 500 V | 2 |
| DC current transfer ratio | CTRDC | 100 |  |  | % | VCE = 10 V, IF = 10 mA | 3 |
| DC current transfer ratio | CTRDC | 40 | 50 |  | % | VCE = 10 V, IF = 10 mA, TA = - 55 °C to + 100 °C | 3 |
| Reverse voltage | VR |  |  | 6 | V |  | 1 |
| Forward current | IF |  |  | 50 | mA |  | 1 |
| Surge current | IFSM |  |  | 1 | A | t ≤ 10 μs | 1 |
| Input power dissipation | Pdiss |  |  | 70 | mW | INPUT | 1 |
| Collector emitter breakdown voltage | VCEO |  |  | 70 | V |  | 1 |
| Emitter base breakdown voltage | VEBO |  |  | 7 | V |  | 1 |
| Collector current | IC |  |  | 50 | mA |  | 1 |
| Collector current | IC |  |  | 100 | mA | t ≤ 1 ms | 1 |
| Output power dissipation | Pdiss |  |  | 70 | mW | OUTPUT | 1 |
| Isolation test voltage | VISO |  |  | 5000 | VRMS |  | 1 |
| Isolation resistance | RIO |  |  | 1012 | Ω | VIO = 500 V, Tamb = 25 °C | 2 |
| Isolation resistance | RIO |  |  | 1011 | Ω | VIO = 500 V, Tamb = 100 °C | 2 |
| Storage temperature | Tstg | -55 |  | 150 | °C |  | 2 |
| Operating temperature | Tamb | -55 |  | 100 | °C |  | 2 |
| Junction temperature | Tj |  |  | 100 | °C |  | 2 |
| Soldering temperature | Tsld |  |  | 260 | °C | max.10 s dip soldering: distance to seating plane ≥ 1.5 mm | 2 |
| Junction capacitance | Cj |  | 50 |  | pF | VR = 0 V, f = 1 MHz | 2 |
| Capacitance | CO |  | 25 |  | pF | VR = 0 V, f = 1 MHz | 2 |
| Collector emitter capacitance | CCE |  | 6 |  | pF | VCE = 0 | 2 |
| Capacitance, input output | CIO |  | 0.6 |  | pF | f = 1 MHz | 2 |
| Switching time | ton, toff |  |  | 10 | μs | VCC = 10 V, IC = 2 mA, RL = 100 Ω | 3 |

## CAD (KiCad official)

- Symbol: `4N37`
- Footprint: `Package_DIP:DIP-6_W7.62mm`
- 3D model: DIP-6 (KiCad packages3D, STEP)
- 3D model files: `4n37-etched.step` / `4n37-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `4n37.step` / `4n37.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [Vishay Intertech datasheet](docs/4n37-datasheet.pdf) (7 pp, sha256 `c7a6ec386422bf8d`, retrieved 2026-10-26, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text), consensus `claude-sonnet-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/4n37-datasheet.pdf)