# MMBTH81

**onsemi** · Bipolar (BJT) · SOT-23

MMBTH81 from onsemi, 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 | B | passive | Base terminal of the PNP RF transistor; the datasheet's emitter-base reverse limit is VEBO 3.0 V and the IEBO test uses VEB = 2.0 V. |
| 2 | E | passive | Emitter terminal of the PNP RF transistor; the datasheet rates the emitter-base breakdown at V(BR)EBO 3.0 V minimum with IE = 10 µA. |
| 3 | C | passive | Collector terminal of the PNP RF transistor; the datasheet limits are VCEO 20 V, VCBO 20 V and continuous IC 50 mA. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | onsemi |
| 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 |
|---|---|---|---|---|---|---|---|
| Collector-Emitter Voltage | VCEO |  |  | 20 | V |  | 2 |
| Collector-Base Voltage | VCBO |  |  | 20 | V |  | 2 |
| Emitter-Base Voltage | VEBO |  |  | 3 | V |  | 2 |
| Collector Current - Continuous | IC |  |  | 50 | mA |  | 2 |
| Operating and Storage Junction Temperature Range | TJ, Tstg | -55 |  | 150 | °C |  | 2 |
| Total Device Dissipation | PD |  |  | 225 | mW | TA = 25°C; device mounted on FR-4 PCB 1.6" X 1.6" X 0.06" | 2 |
| Thermal Resistance, Junction to Ambient | RθJA |  |  | 556 | °C/W | Device mounted on FR-4 PCB 1.6" X 1.6" X 0.06" | 2 |
| Thermal Resistance, Junction to Case | RθJC |  |  | 125 | °C/W |  | 2 |
| Collector-Emitter Breakdown Voltage | V(BR)CEO | 20 |  |  | V | IC = 1.0 mA, IB = 0 | 3 |
| Collector-Base Breakdown Voltage | V(BR)CBO | 20 |  |  | V | IC = 10 µA, IE = 0 | 3 |
| Emitter-Base Breakdown Voltage | V(BR)EBO | 3 |  |  | V | IE = 10 µA, IC = 0 | 3 |
| Collector Cutoff Current | ICBO |  |  | 100 | nA | VCB = 10 V, IE = 0 | 3 |
| Emitter Cutoff Current | IEBO |  |  | 100 | nA | VEB = 2.0 V, IC = 0 | 3 |
| DC Current Gain | hFE | 60 |  |  |  | IC = 5.0 mA, VCE = 10 V | 3 |
| Collector-Emitter Saturation Voltage | VCE(sat) |  |  | 0.5 | V | IC = 5.0 mA, IB = 0.5 mA | 3 |
| Base-Emitter On Voltage | VBE(on) |  |  | 0.9 | V | IC = 5.0 mA, VCE = 10 V | 3 |
| Current Gain - Bandwidth Product | fT | 600 |  |  | MHz | IC = 5.0 mA, VCE = 10 V, f = 100 MHz | 3 |
| Collector-Base Capacitance | Ccb |  |  | 0.85 | pF | VCB = 10 V, IE = 0, f = 1.0 MHz | 3 |
| Collector Emitter Capacitance | Cce |  |  | 0.65 | pF | VCB = 10 V, IB = 0, f = 1.0 MHz | 3 |

## CAD (KiCad official)

- Symbol: `MMBTH81`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `mmbth81-etched.step` / `mmbth81-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmbth81.step` / `mmbth81.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [onsemi datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8586188983088910336) (13 pp, sha256 `6401dce6c10b9144`, retrieved 2026-10-09, tier: lcsc)
- **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/mmbth81-datasheet.pdf)