# 2N3904U

**CBI** · Bipolar (BJT) · SOT-89

2N3904U from CBI, in a SOT-89. 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 | B | input | Base; emitter-base voltage VEBO max 6 V. |
| 2 | C | passive | Collector (also the tab on SOT-89); VCBO 60 V, VCEO 40 V, IC continuous 0.2 A, PC 0.5 W. |
| 3 | E | passive | Emitter of the NPN transistor. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | CBI |
| Package | SOT-89 |
| Category | Transistors/Thyristors |
| Pins | 3 |

## 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-base breakdown voltage | V(BR)CBO | 60 |  |  | V | IC=10μA,IE=0 | 1 |
| Collector-emitter breakdown voltage | V(BR)CEO | 40 |  |  | V | IC=1mA,IB=0 | 1 |
| Emitter-base breakdown voltage | V(BR)EBO | 6 |  |  | V | IE=10μA,IC=0 | 1 |
| Collector cut-off current | ICBO |  |  | 0.05 | μA | VCB=30V,IE=0 | 1 |
| Emitter cut-off current | IEBO |  |  | 0.05 | μA | VEB=6V,IC=0 | 1 |
| DC current gain | hFE(1) | 60 |  |  |  | VCE=1V,IC=0.1mA | 1 |
| DC current gain | hFE(2) | 80 |  |  |  | VCE=1V,IC=1mA | 1 |
| DC current gain | hFE(3) | 100 |  | 300 |  | VCE=1V,IC=10mA | 1 |
| DC current gain | hFE(5) | 30 |  |  |  | VCE=1V,IC=100mA | 1 |
| Collector-emitter saturation voltage | VCE(sat)1 |  |  | 0.2 | V | IC=10mA,IB=1mA | 1 |
| Collector-emitter saturation voltage | VCE(sat)2 |  |  | 0.3 | V | IC=50mA,IB=5mA | 1 |
| Base-emitter saturation voltage | VBE(sat)1 | 0.65 |  | 0.85 | V | IC=10mA,IB=1mA | 1 |
| Base-emitter saturation voltage | VBE(sat)2 |  |  | 0.95 | V | IC=50mA,IB=5mA | 1 |
| Transition frequency | fT | 300 |  |  | MHz | VCE=20V,IC=10mA,f=100MHz | 1 |
| Collector capacitance | Cc |  |  | 4 | pF | VCB=5V,IE=0,f=1MHz | 1 |
| Emitter capacitance | Ce |  |  | 8 | pF | VEB=0.5V,IC=0,f=1MHz | 1 |
| Noise figure | NF |  |  | 5 | dB | VCE=5V,Ic=0.1mA,f=10Hz-15.7kHz, RS=1KΩ | 1 |
| Collector cut-off current (ICEX) | ICEX |  |  | 0.05 | μA | VCE=30V,VBE(off)=3V | 1 |
| Collector-base voltage | VCBO |  |  | 60 | V |  | 1 |
| Collector-emitter voltage | VCEO |  |  | 40 | V |  | 1 |
| Emitter-base voltage | VEBO |  |  | 6 | V |  | 1 |
| Collector current - continuous | IC |  |  | 0.2 | A |  | 1 |
| Collector power dissipation | PC |  |  | 0.5 | W |  | 1 |
| Junction temperature | TJ |  |  | 150 | ℃ |  | 1 |
| Storage temperature | Tstg | -55 |  | 150 | ℃ |  | 1 |

## CAD (KiCad official)

- Symbol: `2N3904U`
- Footprint: `Package_TO_SOT_SMD:SOT-89-3`
- 3D model: SOT-89 (KiCad packages3D, STEP)
- 3D model files: `2n3904u-etched.step` / `2n3904u-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `2n3904u.step` / `2n3904u.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [CBI datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588954794136780800) (2 pp, sha256 `e57155aa22dcf8e5`, retrieved 2026-10-17, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-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/2n3904u-datasheet.pdf)