# FMMT491TC

**Diodes Incorporated** · Bipolar (BJT) · SOT-23

FMMT491TC from Diodes Incorporated, 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 | B | input | Base of the NPN transistor; the base current rating is IB 200 mA, with VEBO 7 V maximum. |
| 2 | E | passive | Emitter of the NPN transistor; the emitter-base voltage rating is VEBO 7 V maximum. |
| 3 | C | passive | Collector of the NPN transistor; ratings are VCEO 60 V, VCBO 80 V, IC 1 A continuous and ICM 2 A peak. |

## Key specifications

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

## CAD (KiCad official)

- Symbol: `FMMT491TC`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `fmmt491tc-etched.step` / `fmmt491tc-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `fmmt491tc.step` / `fmmt491tc.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Diodes Incorporated datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588906217477443584) (7 pp, sha256 `c149432cdb96aa55`, retrieved 2026-10-09, 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/fmmt491tc-datasheet.pdf)