# BLM3401

**BL Shanghai Belling** · MOSFETs · SOT-23

BLM3401 from BL Shanghai Belling, 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; VGS absolute maximum ±20V, gate threshold -0.7V to -1.3V at ID=-250µA, and the device operates with gate voltages as low as -2.5V. |
| 2 | S | passive | Source of the P-channel MOSFET; the diode forward voltage VSD is -1.2V max at IS=-1A. |
| 3 | D | passive | Drain; VDS is -30V max, continuous ID is -4.2A and pulsed IDM is -30A. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | BL Shanghai Belling |
| Package | SOT-23 |
| Category | Transistors/Thyristors |
| 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 | BVDSS | -30 |  |  | V | VGS=0V ID=-250μA | 1 |
| Zero Gate Voltage Drain Current | IDSS |  |  | -1 | μA | VDS=-24V,VGS=0V | 1 |
| Gate-Body Leakage Current | IGSS | -100 |  | 100 | nA | VGS=±20V,VDS=0V | 2 |
| Gate Threshold Voltage | VGS(th) | -0.7 |  | -1.3 | V | VDS=VGS,ID=-250μA | 2 |
| Drain-Source On-State Resistance | RDS(ON) |  | 50 | 55 | mΩ | VGS=-10V, ID=-4.2A | 2 |
| Drain-Source On-State Resistance | RDS(ON) |  | 64 | 72 | mΩ | VGS=-4.5V, ID=-4A | 2 |
| Drain-Source On-State Resistance | RDS(ON) |  | 95 | 120 | mΩ | VGS=-2.5V, ID=-1A | 2 |
| Diode Forward Voltage | VSD |  |  | -1.2 | V | VGS=0V,IS=-1A | 2 |
| Drain-Source Voltage | VDS |  |  | -30 | V | TA=25℃ unless otherwise noted | 1 |
| Gate-Source Voltage | VGS | -20 |  | 20 | V | TA=25℃ unless otherwise noted | 1 |
| Drain Current-Continuous | ID |  |  | -4.2 | A | TA=25℃ unless otherwise noted | 1 |
| Drain Current-Pulsed | IDM |  |  | -30 | A | Note 1: repetitive rating, pulse width limited by maximum junction temperature | 1 |
| Maximum Power Dissipation | PD |  |  | 1.2 | W | TA=25℃ unless otherwise noted | 1 |
| Operating Junction and Storage Temperature Range | TJ,TSTG | -55 |  | 150 | ℃ |  | 1 |
| Thermal Resistance, Junction-to-Ambient | RθJA |  | 104 |  | ℃/W | Surface mounted on FR4 board, t ≤ 10 sec (Note 2) | 1 |

## CAD (KiCad official)

- Symbol: `BLM3401`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `blm3401-etched.step` / `blm3401-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `blm3401.step` / `blm3401.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [BL Shanghai Belling datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8586178614127153152) (6 pp, sha256 `925a8cb0af8b5e0b`, 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/blm3401-datasheet.pdf)