# FMMT618

**Changjing** · Bipolar (BJT) · SOT-23

FMMT618 from Changjing, in a SOT-23. 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; base current is rated up to 0.5 A (IB) and emitter-base voltage up to 5 V (VEBO). |
| 2 | EMITTER | passive | Emitter terminal; emitter-base voltage is limited to 5 V (VEBO) and the device is rated for an operating junction and storage range of -55 to +150 ℃. |
| 3 | COLLECTOR | passive | Collector terminal; continuous collector current is rated up to 2.5 A (IC) with collector-emitter voltage up to 20 V (VCEO). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | SOT-23 |
| Category | Transistors/Thyristors |
| Pins | 3 |

## CAD (KiCad official)

- Symbol: `FMMT618`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `fmmt618-etched.step` / `fmmt618-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `fmmt618.step` / `fmmt618.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/8588948123125493760) (5 pp, sha256 `545b7d2e42682366`, retrieved 2026-10-09, 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/fmmt618-datasheet.pdf)