component

MMBT3904

Public Made by Adom

by adom

Diodes Inc NPN small-signal transistor, SOT-23. 40 V, 200 mA, hFE 100-300, fT 300 MHz. Datasheet-verified.

componenttransistorbjtnpnsot-23diodes-incorporated
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Made with kicad-footprint-generator 10.0 · KiCad file format 20260206
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docs mmbt3904: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 1mo ago
viewers viewers: adom-lbr per-slot symbol + footprint (cross-highlight, pin table) · Ray 2mo ago
mmbt3904-etched.fit.json mmbt3904: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 1mo ago
mmbt3904-etched.glb mmbt3904: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 1mo ago
mmbt3904-etched.step mmbt3904: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 1mo ago
MMBT3904.adom-lbr.json MMBT3904: validated Fusion/EAGLE library + adom-lbr hub, generated from this page's KiCad sources · Ray 2mo ago
mmbt3904.glb Publish 0.1.0 · Ray 2mo ago
mmbt3904.kicad_mod Publish 0.1.0 · Ray 2mo ago
mmbt3904.kicad_sym symbol: flatten derived MMBT3904 to self-contained (renderable) symbol · Ray 2mo ago
mmbt3904.lbr add validated EAGLE .lbr (Fusion library) · Ray 2mo ago
MMBT3904.lbr MMBT3904: validated Fusion/EAGLE library + adom-lbr hub, generated from this page's KiCad sources · Ray 2mo ago
mmbt3904.step add .step (Fusion 3D source) · Ray 2mo ago
package.json Publish 0.1.0 · Ray 2mo ago
page.json mmbt3904: component.models_3d pose record per STEP (Z-up, seated z=0, pad-centre origin, identity binding) · Ray 1mo ago
README.md mmbt3904: laser-etched CAD + chip hero (factory 2.0.0 backfill) · Ray 1mo ago

MMBT3904

Diodes Incorporated · NPN bipolar transistor · SOT-23

Surface-mount NPN small-signal bipolar junction transistor in a SOT-23 package, the SMD counterpart of the 2N3904. Rated for 40 V collector-emitter, 200 mA collector current, with a DC current gain of 100-300 at 10 mA and a 300 MHz transition frequency. Suited to general-purpose amplification and switching. Package marking is K1N.

Pinout

Pin Name Type Function
1 B input Base terminal of the NPN BJT. Controls collector current via base drive; VBE(sat) = 0.65-0.95V at IC = 10-50mA. Emitter-Base breakdown voltage BVEBO = 6.0V.
2 E passive Emitter terminal of the NPN BJT. Typically tied to circuit common or emitter-degeneration network. Emitter-Base breakdown voltage BVEBO = 6.0V.
3 C passive Collector terminal of the NPN BJT. Collector-Emitter breakdown BVCEO = 40V, Collector-Base breakdown BVCBO = 60V, max collector current IC = 200mA.

Key specifications

Parameter Value
Type NPN small-signal BJT
Collector-emitter voltage (VCEO) 40 V
Collector-base voltage (VCBO) 60 V
Emitter-base voltage (VEBO) 6 V
Collector current (IC) 200 mA
DC current gain (hFE) 100-300 @ IC = 10 mA
Transition frequency (fT) 300 MHz
Package SOT-23
Body (L×W×H) 2.9 × 1.3 × 1.1 mm

Ordering variants

Same part, different packaging or reel option.

  • MMBT3904-7-F
  • MMBT3904-13-F

CAD (KiCad official)

  • Symbol: Transistor_BJT:MMBT3904
  • Footprint: Package_TO_SOT_SMD:SOT-23
  • 3D model: SOT-23 (KiCad packages3D)
  • 3D model files: mmbt3904-etched.step / mmbt3904-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); mmbt3904.step / mmbt3904.glb are the bare package body.

Provenance

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

  • Datasheet: Diodes Incorporated datasheet (7 pp, sha256 483284b10e2a58c8, retrieved 2026-08-17, tier: manufacturer)
  • Extractor: ds2sf (Claude) — every pin and dimension is cited to a datasheet page; refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF