SPICE BJT modeling Archives

BJT bipolar transistors require a certain number of parameters to get a good model.The syntax for this model is:

.model ModelNameNPN (par1=a par2=b………parn=x)

for PNP case:

.model ModelNamePNP (par1=a par2=b………parn=x)

where par1 par2…….parn are the parameters that allow to model equations of the BJT.

The main parameters for a reasonable modeling of the behavior of the component are summarized in the following table:

Parameters	Description	Units	Default Value
IS	Transport saturation current	A	1e-16
XTI	IS temperature effect exponent	no unit dimension	3.0
EG	Bandgap voltage (barrier height)	eV	1.11
VAF	Forward Early voltage	V	Infinite
BF	Ideal maximum forward beta	no unit dimension	100
ISE	Base-emitter leakage saturation current	A	0
NE	Base-emitter leakage emission coefficient	no unit dimension	1.5
IKF	Corner for forward-beta high-current roll-off	A	Infinite
NK	High-current roll-off coefficient	no unit dimension	0.5
XTB	Forward and reverse beta temperature coefficient	no unit dimension	0
BR	Ideal maximum reverse beta	no unit dimension	1.0
ISC	Base-collector leakage saturation current	A	0
NC	Base-collector leakage emission coefficient	no unit dimension	2.0
IKR	Corner for reverse-beta high-current roll-off	A	Infinite
RC	Collector ohmic resistance	Ohm	0
CJC	Base-collector zero-bias p-n capacitance	F	0
MJC	Base-collector p-n grading factor	no unit dimension	0.33
VJC		V	0.75
FC	Forward-bias depletion capacitor coefficient	no unit dimension	0.5
CJE	Base-emitter zero-bias p-n capacitance	F	0
MJE	Base-emitter p-n grading factor	no unit dimension	0.33
VJE	Base-emitter built-in potential	V	0.75
TR	Ideal reverse transit time	sec	1e-8
TF	Ideal forward transit time	sec	0
ITF	Transit time dependency on Ic	A	0
XTF	Transit time bias dependence coefficient	no unit dimension	0
VTF	Transit time dependency on Vbc	V	Infinite
RB	Zero-bias (maximum) base resistance	Ohm	0

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Tag Archives: SPICE BJT modeling