# 2SB1261

**Changjing** · Bipolar (BJT) · TO-252-2L

2SB1261 from Changjing, in a TO-252-2L. 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 | BASE | input | Base terminal of the PNP transistor; the emitter-base voltage is rated VEBO -7 V with a maximum base-side breakdown of -7 V (E-B breakdown V(BR)EBO -7 V at IE=-100µA). |
| 2 | COLLECTOR | passive | Collector terminal of the PNP transistor; rated VCBO -60 V and VCEO -60 V with a maximum collector current IC of -3 A. |
| 3 | EMITTER | passive | Emitter terminal of the PNP transistor, rated for VEBO -7 V and operating within the junction/storage range of -55 to +150 ℃. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | TO-252-2L |
| 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-Emitter Voltage | VCEO |  |  | -60 | V |  | 1 |
| Collector-Base Voltage | VCBO |  |  | -60 | V |  | 1 |
| Emitter-Base Voltage | VEBO |  |  | -7 | V |  | 1 |
| Collector Current | IC |  |  | -3 | A |  | 1 |
| Collector Power Dissipation | PC |  |  | 1 | W |  | 1 |
| Operation Junction and Storage Temperature Range | TJ,Tstg | -55 |  | 150 | ℃ |  | 1 |
| Thermal Resistance From Junction To Ambient | RθJA |  |  | 125 | ℃/W |  | 1 |
| Collector-base breakdown voltage | V(BR)CBO | -60 |  |  | V | IC=-100µA,IE=0 | 2 |
| Collector-emitter breakdown voltage | V(BR)CEO | -60 |  |  | V | IC=-1mA,IB=0 | 2 |
| Emitter-base breakdown voltage | V(BR)EBO | -7 |  |  | V | IE=-100µA,IC=0 | 2 |
| Collector cut-off current | ICBO |  |  | -10 | μA | VCB=-60V,IE=0 | 2 |
| Emitter cut-off current | IEBO |  |  | -10 | μA | VEB=-7V,IC=0 | 2 |
| DC current gain hFE(1) | hFE(1) | 60 |  |  |  | VCE=-2V, IC=-0.2A; pulse test | 2 |
| DC current gain hFE(2) | hFE(2) | 100 |  | 400 |  | VCE=-2V, IC=-0.6A; pulse test | 2 |
| DC current gain hFE(3) | hFE(3) | 50 |  |  |  | VCE=-2V, IC=-2A; pulse test | 2 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | -0.3 | V | IC=-1.5A,IB=-0.15A; pulse test | 2 |
| Base-emitter saturation voltage | VBE(sat) |  |  | -1.2 | V | IC=-1.5A,IB=-0.15A; pulse test | 2 |
| Collector output capacitance | Cob |  |  | 40 | pF | VCB=-10V,IE=0, f=1MHz | 2 |
| Transition frequency | fT | 50 |  |  | MHz | VCE=-5V,IC=-1.5A | 2 |

## CAD (KiCad official)

- Symbol: `2SB1261`
- Footprint: `Package_TO_SOT_SMD:TO-252-2`
- 3D model: TO-252-2L (KiCad packages3D, STEP)
- 3D model files: `2sb1261-etched.step` / `2sb1261-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `2sb1261.step` / `2sb1261.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Changjing datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588947751027814400) (5 pp, sha256 `cac26ac597db8efe`, retrieved 2026-10-18, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-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/2sb1261-datasheet.pdf)