Component Statements
The VBIC model was developed as a replacement for the SPICE G-P model. The model has four electrical terminals, two thermal terminals, and up to nine internal nodes, depending on the model parameters that the user specifies. VBIC 1.1.5 and VBIC 1.2 are implemented and controlled by model parameter version. Default is version=1.1.5. For more information about the model and the equations, refer to the Spectre Circuit Simulator Device Model Equations manual.
This device is supported within altergroups.
Sample Instance Statement
q1 (1 2 0 0 0) vbjt area=1
Sample Model Statement
model vbjt vbic type=npn is=2e-16 iben=4.5e-15 isp=1e-15 gamm=1.55e-11 ikf=0.0021 ikr=0.0021 vef=15 ver=7 rbi=35 rbx=7 re=3 rs=15 cje=1.5e-14 tf=15e-12 selft=yes rth=1K
Instance Definition
Name c b e [s] [dt] [tl] ModelName parameter=value ...
tl node is the local temperature and the dt node is the rise above the local temperature caused by the thermal power dissipated by the device being modeled by VBIC. Consequently, the tl node can be connected to a thermal network that models heat flow through the substrate and/or between devices. It is not necessary to specify the substrate and the two thermal terminals. If unspecified, the substrate and the tl thermal terminal are connected to ground. However, if the self-heating flag is turned on and dt is not specified, an internal node is created for self-heating. You must specify the substrate terminal if you specify dt, and both substrate and dt must be specified if tl needs to be specified.
It is recommended not to use the tl node because it is not fully supported and using it will degrade the convergence properties. This node was removed in the VBIC 1.2 version. All thermal effects can be modeled with just the dt node.
Instance Parameters
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area=1
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The area factor of the transistor.
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m=1
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Multiplicity factor.
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region=fwd
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Estimated operating region. Spectre generates output number (0-4) in a rawfile. Possible values are off, fwd, rev, sat, or breakdown.
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trise
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Temperature rise from ambient.
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dtmp
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Alias to trise.
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dtemp
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Alias to trise.
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isnoisy=yes
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Determines if the device should generate noise. Possible values are no or yes.
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small-signal model parameters
Model Definition
model modelName vbic parameter=value ...
Model Parameters
Structural parameters
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type=npn
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The type of transistor. Possible values are npn or pnp.
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compatible=spectre
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Encourages device equations to be compatible with a foreign simulator. This option does not affect the input syntax. Possible values are spectre, spice2, spice3, cdsspice, spiceplus, eldo, sspice, or mica.
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Saturation current parameters
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is=1e-16 A
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Transport saturation current (*area).
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ibei=1e-18 A
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Ideal B-E saturation current. (*area).
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iben=0 A
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Nonideal B-E saturation current (*area).
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ibci=1e-16 A
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Ideal B-C saturation current. (*area).
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ibcn=0 A
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Nonideal B-C saturation current (*area).
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isp=0 A
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Parasitic transport saturation current. (*area).
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ibeip=0 A
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Ideal parasitic B-E saturation current (*area).
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ibenp=0 A
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Nonideal parasitic B-E saturation current (*area).
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ibcip=0 A
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Ideal parasitic B-C saturation current (*area).
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ibcnp=0 A
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Non-ideal parasitic B-C saturation current (*area).
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vo=0 V
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Epi drift saturation voltage.
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gamm=0 V
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Epi doping parameter.
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hrcf=1
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High current RC factor.
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wbe=1
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Portion of Ibei from Vbei.
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wsp=1
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Portion of Iccp from Vbep.
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Emission coefficient parameters
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nf=1
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Forward emission coefficient.
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nr=1
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Reverse emission coefficient.
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nei=1
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Ideal B-E emission coefficient.
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nen=2
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Nonideal B-E emission coefficient.
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nci=1
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Ideal B-C emission coefficient.
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ncn=2
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Nonideal B-C emission coefficient.
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nfp=1
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Parasitic forward emission coefficient.
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ncip=1
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Ideal parasitic B-C emission coefficient.
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ncnp=2
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Nonideal parasitic B-C emission coefficient.
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Current gain parameters
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ikf=∞ A
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Forward knee current (*area).
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ikr=∞ A
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Reverse knee current (*area).
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ikp=∞ A
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Parasitic knee current (*area).
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Early voltage parameters
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vef=∞ V
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Forward Early voltage.
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ver=∞ V
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Reverse Early voltage.
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Breakdown voltage parameters
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avc1=0
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B-C weak avalanche parameter.
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avc2=0
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B-C weak avalanche parameter.
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Parasitic resistance parameters
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rbi=0 Ω
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Intrinsic base resistance (/area).
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rbx=0 Ω
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Extrinsic base resistance (/area).
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re=0 Ω
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Emitter resistance (/area).
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rs=0 Ω
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Substrate resistance (/area).
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rbp=0 Ω
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Parasitic base resistance (/area).
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rcx=0 Ω
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Extrinsic collector resistance (/area).
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rci=0 Ω
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Intrinsic collector resistance (/area).
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minr=0.01 Ω
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Minimum parasitic resistance.
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Junction capacitance parameters
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cje=0 F
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B-E zero-bias capacitance (*area).
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pe=0.75 V
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B-E built-in potential.
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me=0.33
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B-E grading coefficient.
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aje=-0.5
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B-E capacitance smoothing factor.
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fc=0.9
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Forward-bias depletion capacitance limit.
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cbeo=0 F
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Extrinsic B-E overlap capacitance (*area).
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cjc=0 F
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B-C zero-bias capacitance (*area).
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cjep=0 F
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B-C extrinsic zero-bias capacitance (*area).
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pc=0.75 V
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B-C built-in potential.
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mc=0.33
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B-C grading coefficient.
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ajc=-0.5
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B-C capacitance smoothing factor.
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cbco=0 F
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Extrinsic B-C overlap capacitance (*area).
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qco=0 Coul
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Epi charge parameter.
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cjcp=0 F
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S-C zero-bias capacitance (*area).
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ps=0.75 V
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S-C built-in potential.
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ms=0.33
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S-C grading coefficient.
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ajs=-0.5
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S-C capacitance smoothing factor.
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Transit time and excess phase parameters
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tf=0 s
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Forward transit time.
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tr=0 s
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Reverse transit time.
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td=0 s
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Forward excess-phase delay time.
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qtf=0
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Variation of tf with base width modulation.
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xtf=0
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Coefficient of tf with bias dependence.
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vtf=0
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Coefficient of tf dependence on Vbc.
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itf=0
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Coefficient of tf dependence on Ic.
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Temperature effects parameters
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selft=no
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Flag denoting self-heating. Possible values are no or yes.
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tnom (C)
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Parameters measurement temperature. Default set by options.
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trise=0 C
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Temperature rise from ambient.
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rth=0 Ω
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Thermal resistance, must be given for self-heating.
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cth=0 F
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Thermal capacitance.
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xis=3 V
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Temperature exponent of Is.
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xii=3 V
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Temperature exponent of Ibei, Ibci, Ibeip, and Ibcip.
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xin=3 V
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Temperature exponent of Iben, Ibcn, Ibenp, and Ibcnp.
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tnf=0 V
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Temperature coefficient of Nf.
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tavc=0 V
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Temperature coefficient of Avc2.
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ea=1.12 V
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Activation energy for is.
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eaie=1.12 V
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Activation energy for Ibei.
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eaic=1.12 V
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Activation energy for Ibci/Ibeip.
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eais=1.12 V
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Activation energy for Ibcip.
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eane=1.12 V
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Activation energy for Iben.
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eanc=1.12 V
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Activation energy for Ibcn/Ibenp.
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eans=1.12 V
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Activation energy for Ibcnp.
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xre=0
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Temperature exponent of re.
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xrb=0
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Temperature exponent of rb.
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xrc=0
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Temperature exponent of rc.
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xrs=0
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Temperature exponent of rs.
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xvo=0
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Temperature exponent of vo.
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dtmax=226.85 C
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Maximum expected device temperature. (500 K).
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Noise model parameters
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kfn=0
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B-E flicker (1/f) noise coefficient.
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afn=1
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B-E flicker (1/f) noise exponent.
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bfn=1
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B-E flicker (1/f) noise dependence.
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Junction diode model control parameters
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dskip=yes
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Skip junction calculations if they are reverse-saturated. Possible values are no or yes.
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imelt=10 A
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Explosion current (*area).
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Operating region warning control parameters
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bvbe=∞ V
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B-E breakdown voltage.
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bvbc=∞ V
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B-C breakdown voltage.
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bvce=∞ V
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C-E breakdown voltage.
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bvsub=∞ V
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Substrate junction breakdown voltage.
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vbefwd=0.2 V
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B-E forward voltage.
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vbcfwd=0.2 V
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B-C forward voltage.
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vsubfwd=0.2 V
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Substrate junction forward voltage.
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imax=1 A
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Maximum allowable base current (*area).
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imax1=`imax' A
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Maximum allowable collector current (*area).
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alarm=none
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Forbidden operating region. Possible values are none, off, fwd, rev, or sat.
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DC-mismatch model parameters
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mvt0=0.0 V
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Threshold mismatch intercept.
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New model parameter for Vbic 1.2
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vrt=0 V
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B-C reach-through limiting voltage.
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art=0.1 V
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B-C reach-through limiting smoothing factor .
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ccso=0 F
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Fixed collector-substrate capacitance.
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qbm=0
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Parameter to select SGP qb formulation.
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nkf=0.5
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High current beta rolloff parameter.
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xikf=0
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Parameter of temperature dependence to ikf.
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xrcx=0
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Parameter of temperature dependence to rcx.
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xrbx=0
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Parameter of temperature dependence to rbx.
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xrbp=0
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Parameter of temperature dependence to rbp.
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isrr=1
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Parameter to separate is for forward and reversed parts.
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xisr=0
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Temperature exponent coefficient of isrr.
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dear=0 V
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Activation energy for isrr.
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eap=1.12 V
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Activation energy for isp.
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vbbe=0 V
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B-E breakdown voltage.
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nbbe=1.0
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B-E breakdown emission coefficient.
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ibbe=1.0e-6 A
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B-E breakdown current.
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tvbbe1=0
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First temperature coefficient of vbbe.
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tvbbe2=0
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Second temperature coefficient of vbbe.
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tnbbe=0
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Temperature coefficient for nbbe.
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vers=1.15
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Version control parameter.
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vrev=0
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Revision control parameter.
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dtmp (C)
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Alias to trise.
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dtemp (C)
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Alias to trise.
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version
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Alias to vers.
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rev
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Alias to vrev.
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xrbi
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Alias to xrb.
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xrci
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Alias to xrc.
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Shrink Parameters
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shrink=0.0
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Linear shrink parameter.
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shrink2=0.0
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Area shrink parameter.
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Imax and Imelt
The imax parameter aids in convergence and prevents numerical overflow. The junction characteristics of the device are accurately modeled for the value of current up to imax. If the value of imax exceeds during iterations, the linear model is substituted until the current drops below imax or until convergence is achieved. If convergence is achieved with the current exceeding imax, the results are inaccurate, and a warning message is displayed.
A separate model parameter, imelt, is used as a limit warning for the junction current. This parameter can be set to the maximum current rating of the device. When any component of the junction current exceeds imelt, given that the base and collector currents are composed of many exponential terms, the results become inaccurate and a warning message is displayed. The junction current is linearized to above the value of imelt to prevent arithmetic exception, with the exponential term replaced by a linear equation at imelt.
Operating-Point Parameters
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type=npn
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The type of transistor. Possible values are npn and pnp.
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region=fwd
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Estimated operating region. Spectre generates output number (0-4) in a rawfile. Possible values are off, fwd, rev, sat, and breakdown.
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trise (C)
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Temperature rise from ambient.
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vbe (V)
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Base-emitter voltage.
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vbc (V)
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Base-collector voltage.
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vce (V)
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Collector-emitter voltage.
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vcs (V)
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Collector-substrate voltage.
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temp (C)
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Device temperature.
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ith (A)
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Thermal source.
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ic (A)
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Intrinsic DC collector current. (Icc - Ibc + Igc).
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ib (A)
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Intrinsic DC base current. (Ibe + Ibc - Igc).
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icc (A)
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C-E current.
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ibe (A)
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Intrinsic B-E junction current.
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ibc (A)
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Intrinsic B-C junction current.
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ibex (A)
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BX-E junction current.
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igc (A)
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Breakdown current.
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iccp (A)
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Parasitic transport C-E current.
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ibep (A)
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Parasitic transport B-E current.
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ibcp (A)
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Parasitic transport B-C current.
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betadc (A/A)
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Ratio of external collector current to external base current. (ic_ext/ib_ext).
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rcx_t (Ω)
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Temperature-dependent extrinsic collector resistance (/area).
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rci_t (Ω)
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Temperature-dependent intrinsic collector resistance (/area).
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rbp_t (Ω)
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Temperature-dependent parasitic transistor base resistance (/area).
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rbx_t (Ω)
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Temperature-dependent extrinsic base resistance (/area).
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rbi_t (Ω)
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Temperature-dependent intrinsic base resistance (/area).
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re_t (Ω)
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Temperature-dependent emitter resistance (/area).
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rs_t (Ω)
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Temperature-dependent substrate resistance (/area).
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gm (S)
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Intrinsic small-signal transconductance. (gm = dIcc_dVbe + dIcc_dVbc).
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gpi (S)
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Intrinsic small-signal input conductance. (gpi = dIbe_dVbe).
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go (S)
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Intrinsic small-signal output conductance. (go = -dIcc_dVbc).
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gmu (S)
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Intrinsic small-signal Collector-Base conductance. (gmu = dIbc_dVbc).
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cpi (F)
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Intrinsic small-signal B-E capacitance. Same as cje.
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cmu (F)
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Intrinsic small signal B-C capacitance. Same as cjc.
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betaac (A/A)
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Small-signal common-emitter current gain. (gm/gpi).
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ft (Hz)
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Unity small-signal current-gain frequency.
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dic_dvbe (S)
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Intrinsic dIc/dVbe.
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dic_dvbc (S)
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Intrinsic dIc_dVbc.
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dib_dvbe (S)
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Intrinsic dIb_dVbe.
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dib_dvbc (S)
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Intrinsic dIb_dVbc.
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rbi (Ω)
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Intrinsic base resistance.
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rci (Ω)
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Intrinsic collector resistance.
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rbp (Ω)
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Parasitic transistor base resistance.
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cje (F)
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Intrinsic B-E capacitance.
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cjc (F)
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Intrinsic B-C capacitance.
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cbex (F)
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BX-E junction capacitance.
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cbcx (F)
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B-CX junction capacitance.
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cbep (F)
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Parasitic B-E junction capacitance.
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cbcp (F)
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Parasitic B-C junction capacitance.
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pwr (W)
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Power dissipation.
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Related Topics
VBIC Model (vbic)
VBIC 1.2
VBIC 1.1
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