NPN transistor

Ebers–Moll NPN bipolar transistor.

  • electrical
  • Modelica Standard Library
  • 3 ports
  • 1 parameter
BlockNPN transistorKindnpnLibrarySemiconductors

Description

An NPN bipolar transistor using the Ebers–Moll model with the Early effect, transit-time charge, and junction capacitances.

Example

Transistor switches A CMOS inverter of an NMOS and a PMOS transistor, and NPN and PNP transistors switching loads.

InputGround (Input)VDD 5 VGround (VDD 5 V)PMOSNMOSGround (NMOS)Inverter outGround (out)Input, NPNGround (Input, NPN)VCC 5 VGround (VCC 5 V)R C 1 kΩR B 10 kΩNPNGround (NPN)CollectorGround (collector)Input, PNPGround (Input, PNP)VCC 5 V, PNPGround (VCC 5 V, PNP)R B 10 kΩ (PNP)PNPLoad 1 kΩGround (PNP load)Load voltageGround (load voltage)
In Gradara, select a NPN transistor block and press F1, then choose Open example. It opens as a new model in My models, ready to run.

Also in this example:DC voltageVoltage sensorGroundResistorPulse voltageNMOS transistorPMOS transistorPNP transistor

Ports

Conserving terminals 3

  • Celectrical

    Collector.

  • Belectrical

    Base.

  • Eelectrical

    Emitter. Carries the sum of collector and base currents, less the substrate current.

Parameters

  • Forward betaBf50

    ≥ 0

    Forward current gain β. Positive.

Equations

Modelica
vbe = B.v − E.v, vbc = B.v − C.v
ibe = Is · (exp(vbe / Vt) − 1) + Gbe · vbe, ibc = Is · (exp(vbc / Vt) − 1) + Gbc · vbc
C.i = (ibe − ibc) · (1 − Vak · vbc) − ibc / Br − cbc · d(vbc)/dt − iS
B.i = ibe / Bf + ibc / Br + cbc · d(vbc)/dt + cbe · d(vbe)/dt
iS = −Ccs · d(C.v)/dt
Fixed: Br = 0.1, Is = 0.1 fA, Vt = 25.85 mV, Vak = 0.02 1/V, Tauf = 0.12 ns, Taur = 5 ns, Cje = 0.4 pF, Cjc = 0.5 pF, Ccs = 1 pF, Gbe = Gbc = 1 fS

Implementation

Modelica Standard Library 4.1.0Modelica.Electrical.Analog.Semiconductors.NPN
MSL documentation

Assumptions and limitations

  • Only Bf is adjustable. No base, collector, or emitter series resistance, and no temperature dependence.
  • The substrate is implicitly grounded: Ccs connects the collector to ground.
  • The exponentials continue linearly above 40 · Vt (about 1 V).

See also

Select a block in Gradara and press F1 to open its page offline.