component
2SD1781
Public Made by Adomby adom
Changjing Bipolar (BJT), SOT-23. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdown2SD1781
Changjing · Bipolar (BJT) · SOT-23
2SD1781 from Changjing, 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 | BASE | input | Base terminal of the 2SD1781 NPN transistor; the datasheet's maximum rated emitter-base voltage VEBO is 5 V. |
| 2 | EMITTER | passive | Emitter terminal of the 2SD1781 NPN transistor; the same 5 V maximum emitter-base voltage rating (VEBO) applies across the emitter and base. |
| 3 | COLLECTOR | passive | Collector terminal of the 2SD1781 NPN transistor; the datasheet's maximum ratings are VCBO 40 V, VCEO 32 V and collector current IC 800 mA. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| 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-base breakdown voltage | V(BR)CBO | 40 | V | IC=50μA,IE=0 | 1 | ||
| Collector-emitter breakdown voltage | V(BR)CEO | 32 | V | IC=1mA,IB=0 | 1 | ||
| Emitter-base breakdown voltage | V(BR)EBO | 5 | V | IE=50μA,IC=0 | 1 | ||
| Collector cut-off current | ICBO | 0.5 | μA | VCB=20V,IE=0 | 1 | ||
| Emitter cut-off current | IEBO | 0.5 | μA | VEB=4V,IC=0 | 1 | ||
| DC current gain | hFE(1) | 120 | 390 | VCE=3V,IC=100mA | 1 | ||
| Collector-emitter saturation voltage | VCE(sat) | 0.4 | V | IC=500mA,IB=50mA | 1 | ||
| Transition frequency | fT | 150 | MHz | VCE=5V,IC=50mA,f=100MHz | 1 | ||
| Collector output capacitance | Cob | 10 | pF | VCB=10V,IE=0,f=1MHz | 1 | ||
| Collector-Base Voltage | VCBO | 40 | V | 1 | |||
| Collector-Emitter Voltage | VCEO | 32 | V | 1 | |||
| Emitter-Base Voltage | VEBO | 5 | V | 1 | |||
| Collector Current | IC | 800 | mA | 1 | |||
| Collector Power Dissipation | PC | 200 | mW | 1 | |||
| Operation Junction and Storage Temperature Range | TJ,Tstg | -55 | 150 | ℃ | 1 | ||
| Thermal Resistance From Junction To Ambient | RΘJA | 625 | ℃/W | 1 |
CAD (KiCad official)
- Symbol:
2SD1781 - Footprint:
Package_TO_SOT_SMD:SOT-23 - 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files:
2sd1781-etched.step/2sd1781-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);2sd1781.step/2sd1781.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Changjing datasheet (4 pp, sha256
b0d5a3f7653c931b, retrieved 2026-10-18, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-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).