# SMF4746A

**amsem** · Zener Diodes · SOD-123

SMF4746A from amsem, in a SOD-123. 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 | K | passive | Cathode, marked by the color band; the pin that goes positive in zener (reverse) operation, VZ 18.0 V nominal (17.1 V to 18.9 V) at IZT = 14.0 mA for SMF4746A. |
| 2 | A | passive | Anode, the end without the color band; the 1.0 W zener conducts forward with VF of 1.2 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | amsem |
| Package | SOD-123 |
| Category | Diodes |
| Pins | 2 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Zener voltage | VZ | 17.1 | 18 | 18.9 | V | @ IZT = 14.0 mA (SMF4746A, nominal 18.0 V) | 2 |
| Maximum Zener impedance | ZZT |  |  | 20 | Ω | @ IZT = 14.0 mA | 2 |
| Maximum Zener impedance | ZZK |  |  | 750 | Ω | @ IZK = 0.25 mA | 2 |
| Maximum leakage current | IR |  |  | 5 | µA | @ VR = 13.7 V | 2 |
| Storage temperature range | TSTG | -55 |  | 175 | °C |  | 1 |
| Junction temperature range | TJ | -55 |  | 175 | °C |  | 1 |
| Maximum thermal resistance junction to ambient | RӨJA |  | 170 |  | K/W | Note (2): leads kept at ambient temperature at a distance of 10 mm from case | 1 |

## CAD (KiCad official)

- Symbol: `SMF4746A`
- Footprint: `Diode_SMD:D_SOD-123F`
- 3D model: SOD-123 (KiCad packages3D, STEP)
- 3D model files: `smf4746a-etched.step` / `smf4746a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `smf4746a.step` / `smf4746a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [amsem datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8602918469021421568) (5 pp, sha256 `eb8bcc46788cafda`, retrieved 2026-10-15, 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/smf4746a-datasheet.pdf)