# 1SMA5918BT3G

**onsemi** · Zener Diodes · SMA

1SMA5918BT3G from onsemi, in a SMA. 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 | CATHODE | passive | Pin 1 is the cathode, marked by the polarity band on the SMA package per Style 1; the datasheet states the cathode is indicated by a molded polarity notch or cathode band. |
| 2 | ANODE | passive | Pin 2 is the anode of the Zener diode under SMA Style 1, opposite the cathode polarity band. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | onsemi |
| Package | SMA |
| 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 |
|---|---|---|---|---|---|---|---|
| Reverse Zener Voltage @ IZT | VZ | 4.84 | 5.1 | 5.36 | Volts | @ IZT = 73.5 mA; TA = 25°C; limits guaranteed at thermal equilibrium (Note 4) | 2 |
| Maximum Zener Impedance @ IZT | ZZT |  |  | 4 | ohm | @ IZT = 73.5 mA | 2 |
| Maximum Zener Impedance @ IZK | ZZK |  |  | 350 | ohm | @ IZK = 1.0 mA | 2 |
| Forward Voltage | VF |  |  | 1.2 | V | @ IF = 200 mA; for all types | 2 |
| Maximum DC Zener Current | IZM |  |  | 294 | mA(dc) |  | 2 |
| DC Power Dissipation @ TL = 75°C, measured zero lead length (Note 1) | PD |  |  | 1.5 | W | TL = 75°C; 1 in square copper pad, FR-4 board | 1 |
| DC Power Dissipation @ TA = 25°C (Note 2) | PD |  |  | 0.5 | W | TA = 25°C; FR-4 board, onsemi minimum recommended footprint | 1 |
| Operating and Storage Temperature Range | TJ, Tstg | -65 |  | 150 | °C |  | 1 |
| Thermal Resistance, Junction-to-Lead | RJL |  | 50 |  | °C/W | Measured zero lead length (Note 1) | 1 |
| Thermal Resistance, Junction-to-Ambient | RJA |  | 250 |  | °C/W | FR-4 board, onsemi minimum recommended footprint (Note 2) | 1 |
| Reverse Leakage Current @ VR | IR |  | 2.5 |  | A | @ VR = 1.0 V | 2 |

## CAD (KiCad official)

- Symbol: `1SMA5918BT3G`
- Footprint: `Diode_SMD:D_SMA`
- 3D model: SMA (KiCad packages3D, STEP)
- 3D model files: `1sma5918bt3g-etched.step` / `1sma5918bt3g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `1sma5918bt3g.step` / `1sma5918bt3g.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [onsemi datasheet](https://www.onsemi.com/pdf/datasheet/1sma5918bt3-d.pdf) (6 pp, sha256 `f462474d29a69587`, retrieved 2026-10-21, tier: manufacturer)
- **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/1sma5918bt3g-datasheet.pdf)