# BLM3400

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

BLM3400 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; gate-source voltage limit is ±12 V, with RDS(ON) specified at VGS=2.5V, 4.5V and 10V and threshold 0.7 to 1.4 V. |
| 2 | S | passive | Source terminal of the N-channel MOSFET; continuous drain current is 5.8 A and diode forward current is 2.9 A. |
| 3 | D | passive | Drain; drain-source voltage is 30 V maximum, continuous drain current 5.8 A and pulsed drain current 30 A. |

## 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 Voltage | VDS |  |  | 30 | V |  | 1 |
| Gate-Source Voltage | VGS | -12 |  | 12 | V |  | 1 |
| Drain Current-Continuous | ID |  |  | 5.8 | A |  | 1 |
| Drain Current-Pulsed (Note 1) | IDM |  |  | 30 | A | Repetitive rating, pulse width limited by max junction temperature (Note 1) | 1 |
| Maximum Power Dissipation | PD |  |  | 1.4 | W |  | 1 |
| Operating Junction and Storage Temperature Range | TJ,TSTG | -55 |  | 150 | ℃ |  | 1 |
| Drain-Source Breakdown Voltage | BVDSS | 30 | 33 |  | V | VGS=0V ID=250µA | 1 |
| Zero Gate Voltage Drain Current | IDSS |  |  | 1 | µA | VDS=30V,VGS=0V | 2 |
| Gate-Body Leakage Current | IGSS | -100 |  | 100 | nA | VGS=±12V,VDS=0V | 2 |
| Gate Threshold Voltage | VGS(th) | 0.7 | 0.9 | 1.4 | V | VDS=VGS,ID=250µA | 2 |
| Drain-Source On-State Resistance | RDS(ON) |  | 45 | 59 | mΩ | VGS=2.5V, ID=4A | 2 |
| Drain-Source On-State Resistance | RDS(ON) |  | 34 | 45 | mΩ | VGS=4.5V, ID=2.9A | 2 |
| Drain-Source On-State Resistance | RDS(ON) |  | 31 | 41 | mΩ | VGS=10V, ID=2.9A | 2 |
| Forward Transconductance | gFS | 10 |  |  | S | VDS=5V,ID=2.9A | 2 |
| Diode Forward Voltage (Note 3) | VSD |  | 0.75 | 1.2 | V | VGS=0V,IS=2.9A | 2 |
| Diode Forward Current (Note 2) | IS |  |  | 2.9 | A |  | 2 |
| Input Capacitance | Clss |  | 623 |  | PF |  | 2 |
| Output Capacitance | Coss |  | 99 |  | PF |  | 2 |
| Reverse Transfer Capacitance | Crss |  | 77 |  | PF | VDS=15V,VGS=0V, F=1.0MHz | 2 |
| Turn-on Delay Time | td(on) |  | 3.3 |  | nS |  | 2 |
| Turn-on Rise Time | tr |  | 4.8 |  | nS |  | 2 |
| Turn-Off Delay Time | td(off) |  | 26 |  | nS |  | 2 |
| Turn-Off Fall Time | tf |  | 4 |  | nS | VDD=15V,ID=2.9A VGS=10V,RGEN=3Ω | 2 |
| Total Gate Charge | Qg |  | 9.5 |  | nC |  | 2 |
| Gate-Source Charge | Qgs |  | 1.5 |  | nC |  | 2 |
| Gate-Drain Charge | Qgd |  | 3 |  | nC | VDS=15V,ID=5.8A, VGS=4.5V | 2 |

## CAD (KiCad official)

- Symbol: `BLM3400`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `blm3400-etched.step` / `blm3400-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `blm3400.step` / `blm3400.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/8586189373893185536) (4 pp, sha256 `a9bf7155d32a2fe1`, 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/blm3400-datasheet.pdf)