# FM9919D

**Shenzhen Fuman** · AC-DC Controllers & Regulators · SOP-8

FM9919D from Shenzhen Fuman, in a SOP-8. 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 | GND | power_in | Pin 1 is the internal synchronous rectifier MOS source and must be connected to pins 2 and 3. |
| 2 | GND | power_in | Pin 2 is the internal synchronous rectifier MOS source and must be connected to pins 1 and 3. |
| 3 | GND | power_in | Pin 3 is the chip ground and must be connected to pins 1 and 2. |
| 4 | VCC | power_in | Chip supply pin, with an absolute maximum of -0.3 to 7 V, a start-up voltage of 3.3 V and an undervoltage lockout of 2.9 V. |
| 5 | D | passive | Internal synchronous rectifier MOS drain, rated -0.3 to 45 V, which also supplies VCC during operation. |
| 6 | D | passive | Internal synchronous rectifier MOS drain, rated -0.3 to 45 V, which also supplies VCC during operation. |
| 7 | D | passive | Internal synchronous rectifier MOS drain, rated -0.3 to 45 V, which also supplies VCC during operation. |
| 8 | D | passive | Internal synchronous rectifier MOS drain, rated -0.3 to 45 V, which also supplies VCC during operation. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Shenzhen Fuman |
| Package | SOP-8 |
| Category | Power Management ICs |
| Pins | 8 |

## CAD (KiCad official)

- Symbol: `FM9919D`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `fm9919d-etched.step` / `fm9919d-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `fm9919d.step` / `fm9919d.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Shenzhen Fuman datasheet](docs/fm9919d-datasheet.pdf) (4 pp, sha256 `ec1bba4d7bd8af96`, retrieved 2026-10-28, tier: lcsc)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **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/fm9919d-datasheet.pdf)