BondLib.Semiconductors.NPN

# .BondLib.Semiconductors.NPN

NPN transistor of the Modelica bond graph library

## Information

The NPN element of the bond graph library implements the Ebers-Moll model of a NPN bipolar transistor. The substrate is not shown on the icon layer, as it is assumed grounded. The transistor is assumed to be vertically diffused, as the substrate is connected to the collector, rather than to the base.

The NPN bipolar transistor is a directed ThreePort. The direction of positive power flow is assumed into the model at the base, B, and at the collector, C, whereas it is assumed out of the model at the emitter, E.

The causality of the NPN model is relatively free. However, if there is a causality stroke placed at the collector from the outside, the substrate capacitor will assume differential causality.

    Parameters:

     Bf:    Forward beta coefficient (default value = 50)

     Br:    Reverse beta coefficient (default value = 0.1)

     Is:    Transport saturation current (default value = 1e-16 Amp)

     Vak:   Inverse early voltage (default value = 0.02 /Volt)

     Tauf:  Ideal forward transit time (default value = 0.12e-9 sec)

     Taur:  Ideal reverse transit time (default value = 5e-9 sec)

     Ccs:   Collector-substrate capacitance (default value = 1e-12 F)

     Cje:   Base-emitter zero bias depletion capacitance (default value = 0.4e-12 F)

     Cjc:   Base-collector zero bias depletion capacitance (default value = 0.5e-12 F)

     Phie:  Base-emitter diffusion voltage (default value = 0.8 Volt)

     Me:    Base-emitter gradation exponent (default value = 0.4)

     Phic:  Base-collector diffusion voltage (default value = 0.8 Volt)

     Mc:    Base-collector gradation exponent (default value = 0.333)

     Gbc:   Base-collector leakage conductance (default value = 1e-15 Mho)

     Gbe:   Base-emitter leakage conductance (default value = 1e-15 Mho)

     Vt:    Thermal voltage (default value = 0.02585 Volt)

     EMin:  Minimum exponent (default value = -100)

     EMax:  Maximum exponent (default value = 40)

References:

Vlach, J. and K. Singal (1983), Computer methods for circuit analysis and design, Van Nostrand Reinhold, New York, on page 317 ff.

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