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BC557

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Changjiang Electronics Tech (CJ) Bipolar Transistors - BJT, TO-92. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

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Contents

README

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BC557

Changjiang Electronics Tech (CJ) · Bipolar Transistors - BJT · TO-92

BC557 from Changjiang Electronics Tech (CJ), in a TO-92. 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 COLLECTOR passive Collector of the PNP transistor; BC557 VCEO is -45 V, VCBO is -50 V and continuous collector current is -0.1 A.
2 BASE passive Base of the PNP transistor; BC557 emitter-base voltage limit VEBO is -5 V.
3 EMITTER passive Emitter of the PNP transistor; total device power dissipation is 625 mW at Ta=25°C.

Key specifications

Parameter Value
Manufacturer Changjiang Electronics Tech (CJ)
Package TO-92
Category Transistors
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 -50 V IC=-0.1mA, IE=0 2
Collector-emitter breakdown voltage V(BR)CEO -45 V IC=-2mA, IB=0 2
Emitter-base breakdown voltage V(BR)EBO -5 V IE=-100μA, IC=0 2
Collector cut-off current ICBO -0.1 μA VCB=-45V, IE=0 2
Emitter cut-off current IEBO -0.1 μA VEB=-5V, IC=0 2
DC current gain hFE 120 800 VCE=-5V, IC=-2mA 2
Collector-emitter saturation voltage VCE(sat) -0.3 V IC=-10mA, IB=-0.5mA 2
Collector-emitter saturation voltage VCE(sat) -0.65 V IC=-100mA, IB=-5mA 2
Base-emitter saturation voltage VBE(sat) -0.8 V IC=-10mA, IB=-0.5mA 2
Base-emitter saturation voltage VBE(sat) -1 V IC=-100mA, IB=-5mA 2
Base-emitter voltage VBE -0.55 -0.7 V VCE=-5V, IC=-2mA 2
Transition frequency fT 150 MHz VCE=-5V, IC=-10mA, f=100MHz 2
Collector-base voltage VCBO -50 V Ta=25℃ 1
Collector-emitter voltage VCEO -45 V Ta=25℃ 1
Emitter-base voltage VEBO -5 V Ta=25℃ 1
Collector current-continuous IC -0.1 A Ta=25℃ 1
Collector power dissipation PC 625 mW Ta=25℃ 1
Junction temperature Tj 150 ℃ 1
Storage temperature Tstg -55 150 ℃ 1
Thermal resistance from junction to ambient RθJA 200 ℃/W 1
Base-emitter voltage VBE -0.82 V VCE=-5V, IC=-10mA 2
Collector output capacitance Cob 6 pF VCB=-10V, IE=0, f=1MHz 2

CAD (KiCad official)

  • Symbol: BC557
  • Footprint: Package_TO_SOT_THT:TO-92_Inline
  • 3D model: TO-92 (KiCad packages3D, STEP)
  • 3D model files: bc557-etched.step / bc557-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); bc557.step / bc557.glb are the bare package body.

Provenance

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

  • Datasheet: Changjiang Electronics Tech (CJ) datasheet (4 pp, sha256 81775b75ec2ea3df, retrieved 2026-10-22, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-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