# SI2318

**HXY MOSFET** · MOSFETs · SOT-23

SI2318 from HXY MOSFET, 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 | G | input | Gate; controls the channel, with VGS rated at ±20 V maximum and RDS(ON) specified at VGS=10V and 4.5V. |
| 2 | S | passive | Source; the body diode runs from source to drain, with a source-drain diode current of 1.75 A maximum. |
| 3 | D | passive | Drain; rated for VDS of 40 V and continuous drain current of 5 A at TC=25℃. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | HXY MOSFET |
| Package | SOT-23 |
| Category | Triode/MOS Tube/Transistor |
| Pins | 3 |

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Drain-Source Breakdown Voltage | V(BR)DSS | 40 |  |  | V | VGS=0V ID=250μA | 2 |
| Zero Gate Voltage Drain Current (TA=25℃) | IDSS |  |  | 1 | μA | VDS=40V, VGS=0V | 2 |
| Zero Gate Voltage Drain Current (TA=125℃) | IDSS |  |  | 100 | uA | VDS=40V, VGS=0V | 2 |
| Gate-Body Leakage Current | IGSS | -100 |  | 100 | nA | VGS=±20V, VDS=0V | 2 |
| Gate Threshold Voltage | VGS(TH) | 0.7 | 1.9 | 2.5 | V | VDS=VGS, ID=250μA | 2 |
| Drain-Source On-State Resistance (VGS=10V) | RDS(ON) |  | 30 | 38 | mΩ | VGS=10V, ID=5A | 2 |
| Drain-Source On-State Resistance (VGS=4.5V) | RDS(ON) |  | 36 | 52 | mΩ | VGS=4.5V, ID=4A | 2 |
| Source drain current (Body Diode) | ISD |  |  | 1.75 | A | TA=25℃ | 2 |
| Forward on voltage | VSD |  | 0.79 | 1.2 | V | Tj=25℃, ISD=3.5A, VGS=0V | 2 |
| Drain-Source Voltage | VDS |  |  | 40 | V | TC=25℃ unless otherwise noted | 1 |
| Gate-Source Voltage | VGS | -20 |  | 20 | V | TC=25℃ unless otherwise noted | 1 |
| Drain Current, Continuous (TC=25℃) | ID |  |  | 5 | A | TC=25℃ | 1 |
| Drain Current, Continuous (TC=70℃) | ID |  |  | 4.2 | A | TC=70℃ | 1 |
| Power Dissipation (TC=25℃) | PD |  |  | 1.56 | W | TC=25℃ | 1 |
| Storage Temperature Range | TSTG | -55 |  | 150 | ℃ |  | 1 |
| Operating Junction Temperature Range | TJ | -55 |  | 150 | ℃ |  | 1 |
| Thermal Resistance Junction to ambient | RθJA |  |  | 80 | ℃/W |  | 1 |

## CAD (KiCad official)

- Symbol: `SI2318`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `si2318-etched.step` / `si2318-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `si2318.step` / `si2318.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [HXY MOSFET datasheet](docs/si2318-datasheet.pdf) (5 pp, sha256 `3f3a752e4096e120`, retrieved 2026-10-21, 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/si2318-datasheet.pdf)