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BC857

Public Made by Adom

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ST Semtech Bipolar (BJT), SOT-23. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

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Generated by kicad-footprint-generator · KiCad file format 20260206
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docs Publish 0.1.0 · Ray 22d ago
viewers bc857: viewers · Ray 22d ago
bc857-etched.glb bc857: factory component page (tier=lcsc) · Ray 22d ago
bc857-etched.step bc857: factory component page (tier=lcsc) · Ray 22d ago
bc857-hero.glb bc857: hero GLB from the etched model (keeps the MPN mark) · Ray 22d ago
bc857-hero.overlay.json Publish 0.1.0 · Ray 22d ago
bc857.glb Publish 0.1.0 · Ray 22d ago
bc857.kicad_mod Publish 0.1.0 · Ray 22d ago
bc857.kicad_sym Publish 0.1.0 · Ray 22d ago
bc857.lbr Publish 0.1.0 · Ray 22d ago
bc857.step Publish 0.1.0 · Ray 22d ago
package.json Publish 0.1.0 · Ray 22d ago
page.json bc857: specified limits as data (metadata.characteristics, 22 rows from the datasheet) · Ray 16d ago
README.md bc857: specified limits as data (metadata.characteristics, 22 rows from the datasheet) · Ray 16d ago

BC857

ST Semtech · Bipolar (BJT) · SOT-23

BC857 from ST Semtech, 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 of the PNP transistor; the datasheet gives -VEBO max 5 V and -V(BR)EBO min 5 V at -IE = 1 µA.
2 Emitter passive Emitter of the PNP transistor; the datasheet gives collector current -IC max 100 mA and peak -ICM max 200 mA.
3 Collector passive Collector of the PNP transistor; for BC857 the datasheet gives -VCBO 50 V, -VCEO 45 V, -IC 100 mA and Ptot 200 mW.

Key specifications

Parameter Value
Manufacturer ST Semtech
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
DC current gain, Group A hFE 125 250 at -VCE = 5 V, -IC = 2 mA 2
DC current gain, Group B hFE 220 475 at -VCE = 5 V, -IC = 2 mA 2
DC current gain, Group C hFE 420 800 at -VCE = 5 V, -IC = 2 mA 2
Collector base cutoff current -ICBO 15 nA at -VCB = 30 V 2
Collector base breakdown voltage, BC857/BC860 -V(BR)CBO 50 V at -IC = 10 µA 2
Collector emitter breakdown voltage (CES), BC857/BC860 -V(BR)CES 50 V at -IC = 10 µA 2
Collector emitter breakdown voltage (CEO), BC857/BC860 -V(BR)CEO 45 V at -IC = 10 mA 2
Emitter base breakdown voltage -V(BR)EBO 5 V at -IE = 1 µA 2
Collector emitter saturation voltage -VCE(sat) 0.3 V at -IC = 10 mA, -IB = 0.5 mA 2
Collector emitter saturation voltage -VCE(sat) 0.65 V at -IC = 100 mA, -IB = 5 mA 2
Base emitter on voltage -VBE(on) 0.6 0.75 V at -VCE = 5 V, -IC = 2 mA 2
Base emitter on voltage -VBE(on) 0.82 V at -VCE = 5 V, -IC = 10 mA 2
Current gain bandwidth product fT 100 MHz at -VCE = 5 V, -IC = 10 mA, f = 100 MHz 2
Collector output capacitance Cob 6 pF at -VCB = 10 V, f = 1 MHz 2
Collector base voltage, BC857/BC860 -VCBO 50 V 1
Collector emitter voltage, BC857/BC860 -VCEO 45 V 1
Emitter base voltage -VEBO 5 V 1
Collector current -IC 100 mA 1
Peak collector current -ICM 200 mA 1
Power dissipation Ptot 200 mW 1
Junction temperature Tj 150 °C 1
Storage temperature range Tstg -65 150 °C 1

CAD (KiCad official)

  • Symbol: BC857
  • Footprint: Package_TO_SOT_SMD:SOT-23
  • 3D model: SOT-23 (KiCad packages3D, STEP)
  • 3D model files: bc857-etched.step / bc857-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); bc857.step / bc857.glb are the bare package body.

Provenance

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

  • Datasheet: ST Semtech datasheet (3 pp, sha256 4ff3aaeb20421474, 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