Gummel–Poon model


The Gummel–Poon model is a model of the bipolar junction transistor. It was first described in an article published by Hermann Gummel and H. C. Poon at Bell Labs in 1970.
The Gummel–Poon model and modern variants of it are widely used in the popular circuit simulators such as SPICE. A significant effect that the Gummel–Poon model accounts for is the variation of the transistor and values with the direct current level. When certain parameters are omitted, the Gummel–Poon model reduces to the simpler Ebers–Moll model.

Model parameters

Spice Gummel–Poon model parameters
#NameProperty
modeled		ParameterUnitsDefault
value
1IScurrenttransport saturation currentA1
2BFcurrentideal max. forward beta—100
3NFcurrentforward-current emission coefficient—1
4VAFcurrentforward early voltageV∞
5IKFcurrentcorner for forward-beta high-current roll-offA∞
6ISEcurrentB–E leakage saturation currentA0
7NEcurrentB–E leakage emission coefficient—1.5
8BRcurrentideal max. reverse beta—1
9NRcurrentreverse-current emission coefficient—1
10VARcurrentreverse early voltageV∞
11IKRcurrentcorner for reverse-beta high-current roll-offA∞
12ISCcurrentB–C leakage saturation currentA0
13NCcurrentB–C leakage emission coefficient—2
14RBresistancezero-bias base resistanceΩ0
15IRBresistancecurrent where base resistance falls half-way to its minimumA∞
16RBMresistanceminimum base resistance at high currentsΩRB
17REresistanceemitter resistanceΩ0
18RCresistancecollector resistanceΩ0
19CJEcapacitanceB–E zero-bias depletion capacitanceF0
20VJEcapacitanceB–E built-in potentialV0.75
21MJEcapacitanceB–E junction exponential factor—0.33
22TFcapacitanceideal forward transit times0
23XTFcapacitancecoefficient for bias dependence of TF—0
24VTFcapacitancevoltage describing VBC dependence of TFV∞
25ITFcapacitancehigh-current parameter for effect on TFA0
26PTFexcess phase at frequency = 1/°0
27CJCcapacitanceB–C zero-bias depletion capacitanceF0
28VJCcapacitanceB–C built-in potentialV0.75
29MJCcapacitanceB–C junction exponential factor—0.33
30XCJCcapacitancefraction of B–C depletion capacitance connected to internal base node—1
31TRcapacitanceideal reverse transit times0
32CJScapacitancezero-bias collector–substrate capacitanceF0
33VJScapacitancesubstrate–junction built-in potentialV0.75
34MJScapacitancesubstrate–junction exponential factor—0
35XTBforward- and reverse-beta temperature exponent—0
36EGenergy gap for temperature effect of ISeV1.1
37XTItemperature exponent for effect of IS—3
38KFflicker-noise coefficient—0
39AFflicker-noise exponent—1
40FCcoefficient for forward-bias depletion capacitance formula—0.5
41TNOMparameter measurement temperature°C27