A Computer program for the extraction of bipolar transistor SPICE models

Rochester Institute of Technology

RIT Scholar Works

Theses Thesis/Dissertation Collections

10-1-1992

A Computer program for the extraction of bipolar

transistor SPICE models

Larry Duane Delaney

Follow this and additional works at:http://scholarworks.rit.edu/theses

Recommended Citation

A COMPUTER PROGRAM FOR THE EXTRACTION OF BIPOLAR TRANSISTOR SPICE MODELS

by

Larry Duane Delaney

A Thesis Submitted

in

Partial Fulfillment

of the

Requirements for the Degree of

MASTER OF SCIENCE

in

Electrical Engineering

Approved by: Prof. Lynn Fuller, Thesis Advisor

Prof. Robert E. Pearson

Prof. R. Turkman

Prof. R. Unnikrishnan, Dept. Head

DEPARTMENT OF ELECTRICAL ENGINEERING

COLLEGE OF ENGINEERING

ROCHESTER INSTITUTE OF TECHNOLOGY

ROCHESTER, NEW YORK

A Computer Program for the Extraction of Bipolar Transistor Spice Models

I, Duane Delaney hereby grant permission to the Wallace Memorial

Library of The Rochester Institute of Technology to reproduce my

thesis in whole or in part. Any reproduction will not be for

commercial use or profit.

ABSTRACT

Each year semiconductor manufacturers spend millions of

dollars in the development of new products. It can be very

costly to create on silicon a _newly developed circuit,

especially if it is not _very manufacturable or _poorly

designed. To eliminate risk it is of utmost importance that

circuit simulation be done _correctly in the _early stages of

development. Simulation can _only be as good as the model

being used. Almost all designers whether _{digital, analogue,}

or mixed mode use SPICE to simulate their circuits. SPICE

accuracy is inherently dependent on the discrete element

models _{being used,} i.e. _{transistors, diodes,} mosfets.

Development of models _{usually includes} physical measurements,

SPICE parameter extraction from the measurement _data, and then

SPICE simulation to _verify the extracted model parameters.

This can be a tedious and time _consuming process. To speed _up

this process as well as make it much easier to accomplish, a

computer program has been written to aid in the extraction of

SPICE parameters for bipolar transistors.

To use the program all that is needed is Gummel-Poon

data, collector current vs collector-emitter bias voltage

data, junction capacitance vs voltage _data, and _Ft vs

collector current data. The user can then _methodically choose

a parameter of interest and _vary the value and _immediately see

presentation. The user has the _ability to simulate each of

the above mentioned measurements and view the simulation

simultaneously with the data. _Using this technique the user can _develop the entire SPICE _{model, including} temperature

effects and gain a _very good _working knowledge of parameter

TABLE OF CONTENTS

INTRODUCTION 8

THEORY

9

EQUATIONS 9

Newton-Raphson Technique 15

Parameter Description 20

IS, NF, BF 20

ISE,NE 22

RB, IRB, RBM, RE 24

IKF 26

RC, VAF 28

REVERSE BIAS PARAMETERS 30

CJC, VJC, MJC, XCJC, CJE, VJE, MJE, CJS, VJS,

MJS, FC 31

TF, XTF, VTF, ITF 35

XTI, EG, XTB 38

How to Use the Program 40

Ic, lb vs Vbe 42

Ic-Vce 47

Capacitor 49

Additional Notes 53

Appendix A. Source Code 54

LIST OF FIGURES

Figure 1 NPN Symbol and Conventions 9

Figure 2 NPN _Transistor with Integral limits 11

Figure 3 NPN Small Signal Model 15

Figure 4 _IS, BF 20

Figure 5 Beta-IC 20

Figure 6 ISE 22

Figure 7 _Beta, NE 22

Figure 8 Transistor Crossection 24

Figure 9 IR _Drop 24

Figure 10 IC-IKF 26

Figure 11 Beta-IKF 26

Figure 12 _RC, VAF 28

Figure 13 Junction Capacitance 34

Figure 14 Typical Ft vs Ic Curve 35

Figure 15 Main Menu 40

Figure 16 _Ic, lb vs Vbe _{(Gummel-Poon)} 43

Figure 17 _Ic, lb vs Vbe Bar Menu 44

Figure 18 _Ic, lb vs Vbe Bias Menu 45

Figure 19 _Ic, lb vs Vbe Parameter Menu 46

Figure 20 Ic vs Vce 47

Figure 21 Ic vs Vce Bias Menu 48

Figure 22 Capacitor Screen 49

Figure 23 Ft-Ic Screen 50

INTRODUCTION

The bipolar transistor model extraction program was

written _using the "C" _language

and is designed to be used on

IBM or IBM compatible computers. The program uses the same

"Gummel-Poon"

model of the bipolar transistor that is used in

the SPICE. The model and how it is implemented in the program

are described in detail in the _theory portion of this thesis.

Also, a methodical approach to _using the program is described

THEORY

The circuit symbol and current conventions for an NPN

transistor are shown in figure 1. This paper will discuss NPN

transistors. PNP transistors are handled _similarly with

appropriate changes to the signs of the junction voltages.

Figure 1 NPN

Conventions

Symbol and

EQUATIONS

The Gummel Poon model used _by the SPICE is described by

Collector Current:

Ic=Ii_{x(e "A_e}

^)_ix(e

*^e-l)

Base Current:

^=^x(e _w^-l)-J..x(e

^-i)-ix(e

^-l)

Where: BF = _Forward

maximum ideal current gain

BR = _Inverse

maximum ideal current gain

IS = _{Saturation Current}

ISC = _{Base-collector leakage}

saturation current

ISE = _{Base-emitter leakage}

saturation current

NF = _Forward

current emission coefficient

NR = _{Reverse current emission coefficient}

NE = _Base-emitter leakage _{emission coefficient}

NC = _{Base-collector leakage emission coefficient} VBE = _{applied base-emitter} junction voltage

VBC = _applied base-collector junction _voltage

qb = _normalized

majority base charge

All of these are SPICE parameters except _qb and are

worthwhile to define the normalized _majority base charge, qb.

This parameter provides _{necessary biasing dependency} to the

collector current. In the _following analysis figure 2 defines

all the limits of integration.

Emitter

Space Charge Layer

T

*

xe x e nCx}

^T

xjc X C XC

Collector

Figure 2 NPN Transistor with

Integral limits

First, the total _majority charge in the neutral base

region is given _by equation 3.

Qb= f_{qA-jXp(x) dx (3)}

Where _A^ is the cross sectional area of the base and _{q is} the

electronic charge. The zero bias _majority base charge is

CO Qb0=

f

x'e0 and _x'c0 are the zero bias values of _x'e and _x*c of

figure 2. Now the normalized _majority base charge is defined

by equation 5.

<?i=-(5) 'bo

At low level injection the collector current is given _by

equation 6.

Jc=^^^x[(e^-l)-(e^-l)

f

(6)

Multiplying by Qb0/Qbo yields:

The total _{majority base charge}

including the space charge

layers is given _by equation 8.

Ob=Obo^CjexVb^CjcxVbc+xFxIcf^RxICI

where: _Cje =

Base-emitter junction capacitance

Cjc =

Base-collector junction capacitance

TauF =

Forward base transit time

TauR =

Reverse base transit time

IF and _IR are defined in the next equation

qb is then defined as:

Vk._be V,

^. vbc

"ho "hr, Xr,Xi. , KT~V. . XDX1 var vaf 0bo*qb QboXQb

where: VAF = _Forward

early voltage _Qb0/C^c

VAR = _Reverse

early voltage _Qb0/Cje

The second and third terms model base width modulation

and the last two terms model high level injection. In the

forward mode at high level injection the slope of the natural

log of the collector current vs _Vbe is l/(2Vt). At low level

injection the slope is approximately 1/Vt. This is modeled _by

"32 ₍₁₀₎

or

gi-<7i,xg1-g2=o (H)

Solving for _qb yields:

Qb

2 \

$+*>

(12)

At high level injection:

Qb'fik'

TfXj3xc

(13)

If NF equals 1 which is _usually the case then:

v-iAe V<-1)

T I* _{\ zf}

lf*lxe2V*

QboXl^xe2V<

N

and hence the explanation for the _l/(2Vt) slope mentioned

earlier at _{high level injection.}

Newton-Raphson _Technique

All of these parameters will be discussed in detail later

in this paper. The equivalent small signal circuit used _by

the SPICE to model the bipolar transistor is pictured in

figure 3. On _{examination of} figure 3 it is

readily seen that

vbe and vbe are _dependent on voltage drops created _by Ic' and

across _{rb, re,} and re, Therefore _Ic and _Ib are

transcendental in nature and require numerical techniques to

obtain a solution at a given _biasing configuration. _Ic and _Ib

are both functions of _Vbe and Vbc. Therefore the

Newton-Raphson technique was implemented in the "C"

program due to

it's rapid convergence characteristics.

X. (i+l)

(i+l)

-f^x^.x^)

X_{2 (X1} ,X2 )

(15)

The program runs _iteratively until some small allowable

difference delta is obtained between x1

and x(i+1). x17 x2,

flt and ₂ take on different values as the user interacts with

the program. There are four different modes to use the

program _{in; Gummel-Poon, Ic} vs _{Vce, Ft} vs _Ic, and junction

capacitance vs voltage.

Usually forward Gummel-Poon measurements mean _simply

shorting the base and collector terminals and _{sweeping vbe}

over some range of positive values. For the inverse mode base

and emitter are shorted together and _vbc is swept over some

range of positive values.

When in the Gummel-Poon analysis mode, the Newton-Raphson

variables are defined as follows (forward mode of operation):

*l= vbe X2=

Vbc

fl=

vb'e'-IbK^rb+Ie) _-Ic^re-Vbe (16)

The function fl is acquired _{by applying} Kirchoff's

voltage law to the base emitter _{loop including} a variable

voltage source vb.e, connected between B'

and E' in figure 2.

Similarly f2 is acquired _{by applying} Kirchoff's voltage law to the collector-emitter _{loop including} a variable voltage source

vc,e, connected between C and E' in figure 2.

The _Ic vs _Vce measurements require _forcing a _family of

base currents and _{sweeping Vce} over some range at each base

current. In the _Ic vs _{Vce mode,} the variables are defined as

(forward mode of operation):

Xl= Vbe X2=

Vbc

(1?)

1 -t-bforce bcalculated

Here _Ibsource represents the constant current source value

used for a _Vce sweep. The Newton-Raphson technique minimizes the error between calculated and actual values of base

current. Here _- is acquired in the same _way as in the

Gummel-Poon mode.

In the _Ft vs _Ic mode, the variables are defined as

Xl=_vbe

x2=vbc ₍₁₈₎

1 Lcforce *

ccalculated f2=

Vc'e'-Ic*rc-(Ic+Ib) _*Ze+

Vbc-Vbe

Again _Icsource represents the constant current source

value used for the _Ft measurements. _Usually several different

collector currents are chosen and _Ft is evaluated at each

current value.

Junction capacitances are _usually measured over a _sweep

of reverse bias _{voltages, say} -10 to 0 volts for example. At

forward bias voltages the equation below used _by SPICE is not

valid. SPICE uses other parameters to be discussed later to

model the forward bias region.

C,=

^

v\Mi (I9)

For capacitor modelling, the first three capacitances

measured are used to extract _{Cj0, Phi,} and M

^. Then the

next three and so on until all values are used. The _Cj0,

Phi, and _Mi values extracted at each iteration are averaged

noisy data points. _{It should be noted that for this routine}

to be reliable the data should not be too noisy. Each _step of

the capacitor _{routine is implemented as follows:}

n <i+D

So

(i+l) *

W(i+l) Ml

dCx dcx dCx

dC 2

dC d

dC'. i a<t)i

aw/

6c, 3C, 8C, a<t)i

3m/

5c, 3c, 8c,

dQ1 dMj1 -i

Ci

(20)

Where: _{C1 cimeasured Clcalculated}

C2 =

C2measured ~

C2calculated

f = _{c c}

3 ^measured ^calculated

In each case the Newton-Raphson algorithm is used to

minimize the error between a known and calculated value. The

program limits the number of iterations to _fifty for each bias

value. It will almost always converge before _reaching the

Parameter Description

IS, NF, BF

Gumme I -Poon

Ln

Ic

lb

LnlS/-Vbe

Beta VS Ic

Beta

RF

M

Figure 4 _IS, BF Figure 5 Beta-IC

As seen in figure _4, IS is the collector current O-vbe

intercept on the gummel-poon plot. _Physically IS is defined _by

equation 21.

_ qDnni2Aj

x-co

fp0(x)dx (21)

where _p0(x) is the equilibrium hole concentration in the

neutral base and space charge layers. _Increasing IS will

cause and to move _up on the gummel-poon plot.

NF dictates the slope ₍ on the gummel-poon plot ₎ of _Ic

upto high level _injection, and _Ib in the midcurrent range.

The slope is given _by equation 22. _Increasing NF decreases

the slope while _decreasing NF _obviously increases the slope.

Slope= - (22)

NFxVt

BF is the ideal forward maximum current gain (Ic/Ib).

Increasing BF raises the entire curve on the Beta vs Ic plot

(figure 5). It also causes _Ib to lower on the gummel-poon

plot while _Ic remains fixed. This is explained _by

reexamination of equations 1 and 2 and _noting that _Ib is

inversely proportional to beta while _Ic is independent.

ISE,NE

Gumme 1 -Poon

Ln

Ic

Ib

Ln

ISE

Vbe

Beta VS Ic

Beta BF.

Ic Carrps}

Figure 6 ISE Figure 7 _Beta, NE

Figure 7 shows the phenomena referred to as low current

beta degradation. It is caused _by components of base current

that in other regions of operation are negligible. These

components are recombination of carriers at the surface and

base-emitter space charge layer and formation of emitter-base

surface channels. The major component is base-emitter space

charge layer recombination. It is modeled _by ISE and NE.

Figure 6 shows ISE is the base current 0-vbe intercept on the

gummel-poon plot. NE determines the slope in this region as:

Slope=

NExVr (23)

The slope of beta vs _ln(Ic) in the low current region is

Slope=l- ₍₂₄₎

NE

The high current beta degradation seen in figure 7 is due

to high level injection which was discussed earlier. Here

again the slope of _Ic on the gummel-poon plot is proportional

RB, IRB, RBM, RE

Gumme 1 -Poon

Ln Ic lb

/ / IR d-op

Vbe

Figure 8

Crossection

Transistor Figure 9 IR _Drop

The base resistance of a bipolar transistor is _normally

the largest parasitic resistance present. Figure 8 shows how

the base resistance is composed.

The base resistance is a base current dependent variable

resistor. At low currents the base current follows the path

along the resistor RB in figure 8. At high base currents it

follows the path _along the resistor RBM. This occurs due to

the voltage _drop induced _{by Ib} across RB. There exists a

voltage gradient _along the resistor that more _heavily forward

biases the base-emitter junction nearer the surface rather

than under the emitter. When the base current increases this

junction becomes so _heavily forward biased that almost all of

RBM becomes a _{necessary parameter. IRB is the value of base}

current that produces a base resistance _halfway between RB and

RBM. Spice models this phenomena _using the _following analytic

equation:

R^^RBM+3 _(RB-RBM)\ tmZ

_Z\

z,

where :

z=-144_Ib

, 1+ k

\ tz2

IRB

(26)

lb 24

K2

\j

RE is shown in figure 8 and is _usually small in value.

It's effect is seen in the high base current deviation from a

straight line on the gummel poon plot. _^base causes most of

the deviation though (figure 9). _{Increasing any} of the

resistor values increases the IR _drop of the base current.

IRB controls the base current level at which a significant

IKF

Ln

Ic

lb

Gumme 1 -Poon

IKF

Vbe

Figure 10 IC-IKF

Beta VS Ic

Beta

RF

/

Ic Camps}

Figure 11 Beta-IKF

IKF is a parameter used to calculate qb. _Referring to

the gummel-poon plot IKF is the intersection of the low level

injection region of the collector current with the high level

injection region. Or mathematically:

'KF

N

^boIs _ 2Vr (27)

Where _VKF is the value of _Vbe to get _IC=IKF (see equation 14).

This is the high level injection term for I^. The low level

injection expression for _1^ is given by:

Solving these two equations yields

I^^f

Using IKF therefore eliminates the need to perform the

integration described in equation 4 to get Qb0. Figures 11

and 12 show the effect of _varying IKF. _Increasing IKF moves

the high level injection portion of the collector current

curve _up on the gummel-poon plot. It also moves the high

current degradation region of the beta curve to the right.

RC, VAF

IC vs VCE

VCE

Figure 12 _RC, VAF

Figure 8 shows the components of RC _{( RC1,} RC2, RC3 ).

Surprisingly enough the effect of RC is negligible on _Ic of

the gummel-poon plot. It's effect is seen _mainly in the

saturation area of the _Ic vs _Vce plot. RC _directly controls

the slope of collector current vs Vce. _Increasing RC

decreases the slope in this region of operation. The slope is

actually proportional to _RC+RE, but _generally RE is much

smaller than RC. Here the voltage _drop is approximately:

IJRC+RE) _+VcesaC (30)

cesat and ICRE are usually small compared to ICRC, so

quite often people use the slope in this region to approximate

RC which can lead to error since the slope changes with

sweep.

The effect of _early voltage VAF is _readily seen in the

slope of the I vs V curves in the forward active region of

operation (figure 10). Here a small VAF yields a steeper

slope than a large VAF. AS mentioned earlier, SPICE uses VAF

to model base width modulation _indirectly through qb. Base

width modulation is primarily the result of the _varying base

REVERSE BIAS PARAMETERS

All of the parameters mentioned _up to this point are forward bias parameters. Most of these parameters have a "dual" _in

the reverse bias region of operation. Instead of

repeating descriptions _{already given,} the table below gives

the new parameters with their dual in the forward bias mode

and a brief description.

Parameter Forward Page Description

BR BF 11 Reverse Ideal Maximum current

gain

VAR VAF 16 Reverse _Early Voltage

IKR IKF 17 Reverse knee current

NR NF 11 Reverse current emission

coefficient

TR TF 18 Ideal reverse transit time

ISC ISE 13 Base-collector leakage

saturation current

NC NE 13 Base-collector leakage

CJC, VJC, MJC, XCJC, CJE, VJE, MJE, CJS, VJS, MJS, FC

These are the parameters that are used to model all of

the voltage _{dependent junction capacitances. A short}

description of each follows (refer to figure 3).

CJC=base collector junction capacitance

VJC=base collector junction built in voltage

MJC=base collector junction _grading coefficient

CJE=base emitter junction capacitance

VJE=base emitter junction built in voltage

MJE=base emitter junction _grading coefficient

CJS=collector substrate junction capacitance

VJS=collector substrate junction built in voltage

MJS=collector substrate _grading coefficient

FC=coefficient for forward bias depletion

capacitance formula

XCJC=Fraction of base collector capacitance

attached to external node B' _{in figure} 2.

(determines _Cbcx in figure 3 and equation ₃₄₎

The general form for junction capacitance is as follows:

C,=

^

All of the _{junction parameters are solved}

automatically once

a valid file _{containing data is read into the program.}

It is important to understand the parameters XCJC and FC.

In earlier versions of SPICE the base collector capacitance

was modelled _by one _lump capacitor CJC. Due to the

distributed nature of this capacitance and for added _accuracy

this capacitance can now be broken into two capacitors. One

is internal and one external to _Rb (see figure 3). The

external capacitor becomes

Ccbx= _(l-XCJC)

Cjc (32)

while the internal capacitor becomes

Cjcne^XCJCCjcol* (33)

where XCJC takes values between 1 and 0. This leads to a more

accurate model.

FC is used to model junction capacitance at forward bias.

For slight forward bias values equation 34 is still valid but

beyond a _very slight forward bias equation 34 predicts

infinite capacitance. SPICE avoids this _{by using} a straight

line approximation. _Referring to figure _14, FC becomes the

breakpoint _by the value FC x Phi. A straight line

approximates the capacitance _having the same slope as the

Spice then uses the _following equation in place of equation

34.

c,-a,,-^|

where :

F2=(1-FC)1+^ ₍₃₅₎

F3=l-FC(l+Af.,) (36)

These equations _apply to equations _{32, 33,} and 34 above for the junction capacitance terms. The collector substrate

capacitance is modelled somewhat _differently when forward biased. This is shown in equation 43.

Ccs=CJS(0)

'l^H^I

VJS

The straight line approximation is adequate since once

Capacitance vs VJ

Far EQ.34

SPICE

FC X PHI

pflTl VJ

TF, XTF, VTF, ITF

Figure 14 Typical Ft vs Ic Curve

These parameters are used _by the SPICE to model forward

transit charge. The transition _{frequency Ft} or _unity gain

frequency is determined _by these parameters. _Ft is calculated

in SPICE _by the _following equation:

Ft=

2%{C+_C+Cbcx) (38)

Refer to figure 3 for these parameters.

At low currents _Ft is proportional to gm. As _gm

increases with collector current so does Ft. At still higher

collector currents the base emitter diffusion capacitance

flow _reducing Ft. To see how these parameters affect Ft the

capacitances must be examined. The capacitances are

calculated as follows:

where:

where:

C =x -+C (0)1-*

FV, Je

I

V,_be -M'j

(39)

C'X^+C.JO) vr -jc

(40)

cbcx=cjc(o)

(i-xcjc)\i--^

vb,c\-M>

(41)

xf=rF|i+xrJ

ITF

"be

l.iiVTF (42)

Icc-.i\e^-l cc

Qb

The equation for _Tauf is a _purely empirical formula

derived to fit the _Ft characteristics as a function of

current. The first term in equations 32 and 33 is referred to

diffusion capacitance and models the mobile carrier stored

charge. The second term is referred to as the junction

capacitance. It is set _{up by} the immobile ions present in the

space charge layer.

In conclusion it is seen that _Ft is a function of

transconductance, diffusion capacitance (and thus base

transit _time), and junction capacitance (and thus _Vbe and

XTI, EG, XTB

XTI is the saturation current temperature exponent while

EG is the _energy gap. For a typical bipolar transistor XTI is

3 and EG is 1.12 eV- The temperature dependence of IS is

modelled as follows:

l.iTj-l.iTj _-p

J-

A

where:

2

EG(T) =EG(0) --#^~

a=7.02Z10-4 <45>

P=1108

EG(0) =1.16eV

XTB is the forward and reverse beta temperature

coefficient. The temperature dependence of beta is as

follows:

(j. \XTB

"jT <46>

XTB is also used to model the temperature dependence of

ISE(T2) =ISE(T1) -i

ISC(T2)=ISC(T1)l^-XTBT

XTBT

IS(T2)

JS(r1)

IS{T2)

ISiT^ 1 WE

How to Use the Program

The program can be run from the _floppy disk or copied to

a hard drive and run from the hard drive. At the prompt

simply type "BIP". The program will begin execution and the

following choices will be presented in a menu box.

Ic,Ib vs Vbe

Ic-Vce

Capacitor

Ft-Ic

Include Model

Save model

Temperature-C

Quit

Figure 15 Main Menu

At this point the user should set the temperature if the

data was measured at other than 27 degrees C. _Also, if the

user is verifying a _model, he or she should use the "Include

Model"

choice. The user will be prompted for further

information (i.e. celcius temperature and/or filename of file

containing the SPICE model for verification). The program

will read in _any valid SPICE parameters from an ASCII text

file.

At least six files are needed for complete _modelling of

the bipolar transistor: _Ic, Ib vs _Vbe, Ic vs _Vce,

Capacitor vs voltage _{( base-emitter, base-collector,} and

collector-substrate _), and Ft vs Ic. If temperature

modelling is to be performed, an additional _Ic, Ib vs Vbe

room temperature model should be completed first.

Following is a short description of the various

Ic, Ib vs Vbe

This choice should be the _starting point for _developing

the model. The _necassary data file should be formatted as

follows:

Column 1 _Vbe

Column 2 _Base Current

Column 3 _Collector Current

Column 4 ₍ optional ₎ Beta ₍ Ic/Ib ₎

If beta is not included in the _file, the program will

compute it for each Vbe. After _{initially choosing Ic,} Ib vs

Vbe the screen will appear as in figure 16.

Striking the enter _key at this point will cause the bar

menu to appear as in figure 17. To start the user should use

the arrow keys or mouse to choose the "Data"

menu choice.. If

using the arrow _{keys, striking} enter will choose the highlighted menu choice. If a mouse is used _striking the left

key will choose the menu choice under the cursor. The user

will be prompted for a file. The data will appear as discrete

points on the plot. If the file is not found the user will

not be notified, there will _simply be no data present on the

10 n

1

Ic,IbvsVbe

L .1 J I 'l . I J --J 1 1J L-^_-.l 1

Betav; Ic ; ! 1 '

:- i^ 1

~\

1 ! / i i -i

t

-i- -]

.._;_.. - 1 l

, '.

i i i i T i*

( i

._;....ii__i j___j._ i

i

.1 i

_i._.

.*- ._.__.-_ ~T" --:-~~ \ _r^

;!

i i < i i

]

"T" 1

*---T 1 T ' 1_~

-j---"T

r--i T

:-._;..

i i i i

i i i i

,.,..

i

100

0.3 Vbe(Volts)

Up-Down ArroworEnter

n

1.1 10

Vce=Vbe

10 Ic(Amps) 10

Temp=27.0C

Figure 16 _Ic, Ib vs Vbe _{(Gummel-Poon)}

Next, the user should choose the "Bias"

menu choice.

The screen should appear as in figure 18. The first two

choices, "NPN" and "Forward" will toggle to "PNP"

and

"Reverse" _{respectively.}

Choosing "Forward" will cause forward

mode simulation while "Reverse" will cause reverse mode

simulation. The rest of the choices on the menu are self

explanatory. When the user is satisfied with the bias _setup

he or she should click on "Done".

Finally, the user should select the "Parameter"

earlier in this document _during the simulation to minimize the

10

Increment _I Quit

Ic,IbvsVbe 01

Q

* i i 1 i %'

1 ' ! ;

P' ; _j

i j 1 i ;i i__'__!

1..-..4

._.__; ;./...L^._.i_._i i i i i/ i

!

.f....]/._L._i...i ._. s> t !

/ ' /' ' <

o

s > 1- 1y 1 I

u

-T,"

-T > i- --i-

-r r--

---,....-.:...i... J ;.

-13 ,;;,,,

0.3 Vbe(Volts) 1.1

Up-Down ArroworEnter Vce:

li

10

=Vbe

BetavsIc

._;_.-;-..;.../.'.

-i.-.j-.-^-.j^-.j._.

: , ' , , i ; . ;

! "1 1 1 , I i ; ; !-\

Temp=_{27.0 C}

Figure 17 _Ic, Ib vs Vbe Bar Menu

chance of non-convergence. The parameter chosen will be

incremented or decremented whenever the _up or down arrow keys

are _respectively pressed. The program will run a new

simulation each time a parameter value is changed. To

increase or decrease the amount a parameter is changed with

each _keypress, the user can choose "Increment" from the bar

menu. A value between zero and one should be entered. The

parameter will change as a fraction of it's present value with

each keypress.

that the simulation and data match. This will be obvious when

the simulation curve _{directly overlays the data.}

It should be obvious from figures 16, 17, 18, and 19

that Beta vs Ic is plotted with the so-called gxunmel-poon

plot. This will aid in better _modelling the low and high

current beta _degradation mentioned earlier. This curve is

quite sensitive to the parameters _{BF, ISE, NE,} and IKF.

Replot Data Increment tIBiaS'

Ic,lbvsVbe 01

10

o

8

0

1 r i _.-_J_-._J J_..

1 i i_/

r '\ ,/ , S

. -. 'L-__L .'. 1 .

---

--/

' ' '

.... ... ...

10

0.3 Vbe(Volts)

Up-Down ArroworEnter

Forward

Vce=Vbe Vbestart=0.300

\T>estep=0.050

100

9

0

10

1.1 10 Ic(Amps) 10

Vce=Vbe Temp=27.0 C

Parameter li Replot

Ic,IbvsVbe

~s

hi&liBHiIiM

:.L i_._j.

Vbe(Volts)

Up-Down ArroworEnter

Increment I Bias

Betavslc

...

^ ;...._T j ., ., -i-

---, *

| ; , / , ; , ; -t ;

_J . '. 1. I . 1. J Li_i

1. ti 1 j ...J..-4 I- l___i_-.

I | 1 . i . I I i 100

10

1.1 10 Ic(Amps) 10

Vce=Vbe Temp=27.0C

Ic-Vce

Choosing Ic-Vce from the main menu will result in the

screen _appearing as in figure 20. _{Again, striking} enter will

yield the bar menu. The _only difference in these bar menu

choices and those of the gummel-poon simulation is the "Bias"

option. Figure 21 shows the options available under "Bias".

Again "NPN"

and "Forward" toggle to "PNP"

and "Reverse"

respectively. The rest of the options are self explanatory.

Collector CurrentvsVce 7.0

|

0

- ---

-/

-1.0

(

Up-Down/

(.0 Vce_(Volts) l.C

utow orEnter Ib=5.0e-005 1.0e-004 Temp=27 oc

should be minimized to reduce CPU time. When _modelling Re,

the simulation bias should be such that _only the saturated

region of operation should be used. No information is gained

from the active region and _using this area of operation will

only increase simulation time. Also _only two or at most three

base currents are needed to model Re and _VAF, and quite often

only a few points are needed for an accurate fit. When

modelling VAF, use _only the active region of operation since

no information _regarding VAF is obtained from the saturation

area of operation. The Newton-Raphson trechnique is powerful

but in some instances it _{may have} a difficult time converging.

Parameter IReplot Increment paiae^a^^ Quit

7.0

CollectorCurrentvsi

Forward

Vcstart=0.000

Vcstop=1.000

Vcstep=0.200

lstart=5.00e-005

lstep=5.00e-005

Up-Down ArroworEnter

Vce(Volts)

Ib=5.0e-005 1.0e-004

Bias Menu

1.0

Capacitor

When _using the Capacitor simulation, a data file is

needed that contains the bias voltage in column 1 and

capacitance values in column 2. The user will be prompted for

the capacitor type _{( base-emitter, base-collector,} or

collector-substrate _), and a data file. If the data file is

not found the simulation and fit will not be performed.

The resultant screen should appear as in figure 22. All

related parameters are _{automatically} extracted _by the program.

1.0

8 s

13

U.

o

M

a

0.4 0.0

Base-Emitter CapacitancevsVoltage

: : : :

! i > i

V i

\

V

; ,

'm.

* m

-m *

ft *

Ft-Ic

The Ft vs Ic simulation appears as in figure 23,

FtvsCollectorCurrent 1.50

N

I ,

'

0 y

_^.

/

/

/

1.20 <a 01

10 Ic(Amps) 10

Up-DownArroworEnter Vce=_2.00,3.00 Volts Temp=_{27.0 C}

Figure 23 Ft-Ic Screen

Pressing the enter _key will cause the bar menu to appear.

The _only difference between the choices available here and

those of the _{previously described} screens is the "Parameter"

and "Bias" options. The parameter choices are shown in figure

24. Even though the capacitance values are _{autimatically}

extracted in the capacitor _{simulation, they} are available

here for fine _tuning the _Ft simulation.

The bias options are shown in figure 25. _Again, "NPN"

cases. Here each curve _{is driven by}

Vce much like the Ic-Vce

curves are driven _by base current. _Ic becomes the _sweep

parameter _{for this simulation. Since this is a}

very complex

simulation, care should be taken to minimize the number of

simulation points. It is also important to choose data points

and simulation points that will cover the entire typical _Ft

curve as seen in figure 13. This will require careful and

well thought out choices of _{biasing during} measurement of Ft.

l'.l'i'M wmram

MA-&i.r?gi)Tnii

ggggggai

Increment Bias

FtvsCollector Current

1.20

10

Up-Down ArroworEnter

Ic_(Amps)

Vce=_2.00,3.00 Volts

10

Temp=27.0 C

Parameter 1 Replot | Data

1.50

FtvsCollector Cii |haat^=tSe;Ol2} lcstop=fj.0e-002

lcsteps=10

Ycstart=2.000

Ycstep=1.000

\csteps=2

Up-Down ArroworEnter

Ic(Amps)

Vce=_2.00,3.00 Volts

01

10

Temp=27.0 C

Additional Notes

It is important to save the model that has been developed

regularly throughout the _modelling process. This is done _by

selecting the "Save Model"

option of the main menu ₍ see

figure 15). The user is prompted for a filename for _storing

the model to. This model is a valid ".MODEL" card that can be

used in a SPICE input deck for simulation.

When _using the "Include Model"

option of the main menu,

be careful to include the drive if the file is on other than

the "C" _drive.

This also applies when _choosing the "Data"

option available on the bar menu that appears on each

Appendix A. Source Code

/*

* _SPFT.C

-Finds Spice model for bipolar transistors.

* _Written

by Duane _Delaney 1991 */

/include <graph.h>

/include <stdio.h>

/include <math.h>

/include <malloc.h>

/include <stdlib.h>

/include <conio.h>

/include <ctype.h>

/include <string.h>

/include "menu.h"

/include "mouse.h"

/* _Function

prototypes _*/

void Gummel ₍ void _{) ;}

void _Icvce( void _{) ;}

void Capacitor₍ void _{) ;}

void Ft₍ void _{) ;}

void Save₍ void _{) ;}

void _Incl( char filename_[20_]) ;

void plot(int numcur,int _icount, double y[5_{] [} 100 _{] ,}double x[ 100] ,double xmin,

double _{xmax, double ymin, double} ymax,int _new, short _col,short

writemode,

short _lox, short _loy);

void _{newminmax( double *max,} double *min);

void getgo(int _count,int *chose,int *icur);

void _{pnjlims( double} *vnew, double _*vold);

void plotpix(int _numcur, double _y[5_{][ 100]} ,double x[100],

double _xrange,

double yrange, short _col, int _startcur);

void _{write_text(}short _r, short _c, char _*txt);

void write_ftext₍short _x, short _y, short _i, short _j, unsigned

char *txt);

int choice₍ int x, int y, int numstr, unsigned char

*mnu[20],int _place);

void setvid_{( )} ;

void Spice_{( )} ;

void Temper_{( )} ;

/define MAXLINELEN 81

/* _default

SPICE parameters (mine) */

double f[]=

{

0,1.0E-16, 100. 0 ,1. 0

, 1. 0E2

, 1. OE-2

, 1. OE-16,1.5,1.0,1.0,1.0E2,1

.0E-2, 1.0E-16,2.0,100.0,1.0E-6,10.0,1.0,1.0,1.0,1.11,3.0,100.0E-12 ,0.9,2.0, 1.0E-3,1.0E-9,2.0E-12,0.75,0.33,2.0E-12,0.75,0.33,0.5,1.0, 2.0E-13,0.75,0.5,1.0 };

char _*sp[ ]=

{

"IS" ,

"BF"

, "NF" ,

"VAF" , "IKF" , "ISE" , "NE" , "BR" , "NR" , "VAR" , "IKR" , "ISC",

"NC", "RB", "IRB", "RBM", "RE", "RC", "XTB", "EG", "XTI", "TF", "XTF",

"VTF","ITF",

"TR" ,

"CJE"

, "VJE",

"MJE" , "CJC" , "VJC" , "MJC" , "FC" , "XCJC" , "CJS" ,

"VJS", "MJS","PTF"

};

enum mods

{

BL,IS,BF,NF,VAF,IKF,ISE,NE,BR,NR,VAR,IKR,ISC,NC,RB,IRB,RBM,R E,RC,XTB,

EG,XTI,TF,XTF,VTF,ITF,TR,CJE,VJE,MJE,CJC,VJC,MJC,FC,XCJ,CJS,

VJS,MJS,PTF };

int _{iMode,kind=0,time=0;}

double

bi,ci,vce, vbe,vt,vcrit,incr=._{2,vbcoo, vbeoo, fti,te, je, jc, js;}

double se,sc,si,bfo,bro,vej,vcj,vsj;

unsigned char

*mnustuff_[6_]={"Parameter", "Replot", "Data", "Increment",

"Bias", "Quit" };

unsigned char *mnupar[20_]; unsigned char _*mnuchoice[6_] ;

/* _{type=l npn} -1 _{pnp */}

int _type=l;

char _{oltype[4]="NPN";} /*

Array and enum for main menu _*/ ITEM _{mnuMain[ ]} =

{ /*

9, "Ic,Ib vs Vbe"

0, "Ic-Vce"

0, "Capacitor"

0, "Ft-Ic"

8, "Include Model"

0, "Save Model"

0, "Temperature-C"

0, "Quit"

0, ""

};

/* _{Define constants}

(0, 1, enum CHOICES Highlight Char /* _V /* /* /* /* /* /* /* I C F M S T Q Pos 9 0 0 0 8 0 0 0 */ V V */ V */ */ V V

2,...) for menu choices _*/

GUM, IC, CAP, FT, INCM, SAVE, TEMPER, QUIT

{

};

/* _Arrays

of video mode menu items and of _{corresponding} mode numbers.

* _{Each has}

a _{temporary array containing} all _items, and a pointer version

*

including all except Olivetti. V

ITEM _{mnuModesT[ ]} =

{ 0, 4, 4, 4, 0, 0, 0, 4, 0, 1, 0, /*

ORES COLOR "

MRES4COLOR "

MRESNOCOLOR"

HRESBW"

MRES16COLOR"

HRES 16COLOR" ERESCOLOR"

VRES2C0L0R"

VRES16C0L0R"

'MRES256COLOR"

Highlight Char Pos _V

}/ /* o 0 _V

/* _{4 4}

V

/* _{N 4}

V

/* _{B 4}

V

/* _{M 0}

V

/* _{H 0}

V

/* _{E 0}

V

/* _{2 4}

V

/* _{V 0}

V

/* _{R 4}

V }; ITEM mode *mnuModes = V

&mnuModesT[ 1] ; /* Default is no Olivetti

int _{aModesT[ ]} =

{

16_COLOR,

RES_COLOR,

_VRES2COLOR,

16_COLOR,

_MRES256COLOR,

,

_ERESNOCOLOR,

};

int *aModes =

&aModesT[l];

Olivetti mode _*/

int main( ) {

int rowMid, colMid,i; int fFirstTime =

TRUE;

int iMainCur =

0, iModesCur =

0;

struct _fi;

if(_registerfonts₍ "TMSRB.

FON"

)<=0₎ {_outtext( "you forgot the _fonts");

getchar_{( ) ;}

exit₍1_{) ; }}

if(_setfont₍ "t'_tms

rmn' hl5wl0b"₎<0₎

{_outtext₍"can1_t

set _font");

getchar_{( ) ; }}

if_{(_getfontinfo(&fi) )}

{ _outtext("Can't

get font _info");

exit₍ 1_{) ;}

}

);

&vc _);

rowMid =

vc. numtextrows / 2;

colMid = _{vc.numtextcols}

/ 2;

/*

* _{If no color stop} !

V

switch₍ vc.adapter ₎

{ case

mnuModes = _&mnuModesT

[0_{] ;} Olivetti mode _*/

aModes = _&aModesT[0];

case

mnuModesT[4].achItem[0] = '\0';

/* _{Default is no}

/* _{Turn on}

iMode =

_HERCMONO;

break;

case

mnuModes =

&mnuModesT[0] ; /* Turn on

Olivetti mode _*/

aModes =

&aModesT[0];

case

mnuModesT[7] .achltem[0]

=

'\0'; /* _{Turn off VGA}

modes _*/

if( vc._memory > 64 ₎ iMode = S_COLOR; else iMode = _HRES16C0L0R; break; case mnuModes =

&mnuModesT[0]; /* Turn on

Olivetti mode _*/

aModes = &aModesT[0]; case iMode = _VRES16C0L0R; break; case iMode = _MRES256C0L0R; break; case default:

puts( "No graphics mode available.\n" _);

return _TRUE;

}

switch₍ vc.mode ₎

{ case case case JTEXTMONO: case case

printf( "Color Graphics Required to run Program\n");

exit₍0_{) ;} default: break; } te=300.0; vt=25.86e-3; se=f_[ISE]; sc=f_[ISC]; si=f_[IS]; bfo=f_[BF];

bro=f_[BR_];

vcj=f_[VJC]; vsj=f_[VJS];

je=f_[CJE] jc=f_[CJC] js=f_[CJS]

/* _{Find current}

mode in mode array. _*/

for( iModesCur =

0; aModes_[iModesCur] != _iMode;

iModesCur++ ₎

while₍ TRUE ₎

{

/* _{Set text}

mode and _optionally clear the screen to blue.

V

if_(fFirstTime)

{_setvideomode(_DEFAULTMODE₎ ;

_setbkcolor((long)JTRED );

_clearscreen( );

/* _{Select from menu.} */ MouseInit( ) ;

SetPtrVis(HIDE) ; }

iMainCur=0;

iMainCur =

Menu( rowMid, colMid, mnuMain, iMainCur );

/* _{Branch to menu choice.}

*/

switch₍ iMainCur ₎

{

case GUM: setvid( ) ;

Mouselnit_{( )};

SetPtrVis(HIDE);

Gummel_{( )};

fFirstTime=TRUE;

break; case IC:

setvid( ) ;

Mouselnit_{( )} ;

SetPtrVis(HIDE);

Icvce( ) ;

fFirstTime=TRUE_;

break; case CAP:

Mouselnit_{( ) ;} SetPtrVis(HIDE); Ft();

f_{FirstTime=TRUE}

; break;

case INCM:

kind=3;

Incl("nothing" );

/*setvid( );*/

f_{FirstTime=FALSE;}

break; case SAVE:

Save();

/*setvid( );*/

f_{FirstTime=FALSE;}

break;

case TEMPER:

Temper_{( )} ;

/*setvid( );*/

f_{FirstTime=FALSE;}

break;

case QUIT:

_unregisterfonts( ) ;

( );

return _FALSE;

} } }

void _{setvid( )}

{

( iMode ₎ ;

_displaycursor( );

_getvideoconfig(&vc ); }

void write_text₍short _r, short _c, char _*txt)

{ _settextposition(r,c);

(txt_{) ;} }

void write_ftext₍short _x, short _y, short _i, short _j, unsigned

char _*txt)

{ (x,y) ;

(i, j) ; (txt₎ ;

}

/* _{Gummel Poon}

7

int xwidth,yheight,cols, rows, halfx,halfy, jtencount,icount;

double xminl,xmaxl,yminl,ymaxl,vstart,vstep,vstop; double _{xmin2,xmax2,ymin2,ymax2,beta[2] [100]} ,ic[100]; double _{ii[2] [100] ,v[ 100]} ,val;

char lab_[4_] ,temp[20] ,temp2[20] ; int _{i,j,k,rowMid, colMid,tip;}

static int _vidflag; int _chose=0;

int _{new=0,vbc=0,olwhich=l;}

short _{linecol=10,pixcol=12;}

struct _fi;

kind=l; /* _{tells various routines call comes from gummel}

_getvideoconfig(&vc ); rowMid =

vc. numtextrows / 2;

colMid =

vc.numtextcols _{/ 2;}

xwidth=vc. numxpixels;

yheight=vc.numypixels;

halfx=xwidth/2_;

halfy=7*yheight/8;

cols=vc.numtextcols;

rows=vc. numtextrows;

vstart=0. 3 ;

vstop=1.0;

vstep=0_.05;

start:icount=-l;

vidflag=FALSE;

for₍vbe=vstart; vbe<vstop+vstep ; vbe+=vstep)

{ if(vbc==0) vce=vbe;

Spice();

ii_[0_{] [}++icount_]=logl0₍bi₎ ; ii[l] [icount]=logl0(ci) ; beta_[0_{] [}icount_]=ci/bi_;

ic_[icount_]=ii_[1_{] [}icount] ;

v_[icount_]=type*vbe;

}

time=0_;

if(vbc==0)

vce=0. 0 ;

start2:if₍new==0₎

{xminl=lE21;

{if₍ii_{[ j] [}i_]<yminl₎ yminl=ii_{[j ] [}i_] ; if_{(ii[j] [i]>ymaxl)}

ymaxl=ii[j ] [i]; if(j==l)

{if_{(v[i]<xminl) xminl=v[i];} if_{(v[i]>xmaxl) xmaxl=v[i];}

} }

newminmax₍Sxmaxl_,&xminl_{) ;}

newminmax(&ymaxl,&yminl) ;

_clearscreen( );

if_(iwhich==l)

{write_ftext(10,2*halfy/3,0,l,"Ic and Ib _(Amps)");

write_ftext(xwidth/5,27*yheight/30,l,0,"Vbe (Volts)");

write_ftext(xwidth/5,25,l,0,"Ic, Ib vs _Vbe");

if_(vbc==0)

write_ftext_{(xwidth/2-_getgtextextent(}"Vce=Vbe"

)/2,yheight-15

,l,0,"Vce=Vbe");

else

{ sprintf_(temp,"Vce=%6.3f"

,vce) ;

write_ftext₍xwidth/2-_getgtextextent_(temp)/2,yheight-15,1,0, temp) ; }

}

else

{write_ftext(10,2*halfy/3,0,l,"Ie and Ib _(Amps)"); write_ftext (xwidth/5_,27*yheight/30_,1,0, "Vbc (Volts₎"

) ;

write_ftext(xwidth/5,25, 1,0, "Ie, Ib vs _Vbc");

if_(vbc==0)

write_ftext₍xwidth/2-40_,yheight-15_,1,0, "Vec=Vbc"

) ; else

{ sprintf_(temp, "Vce=%6. 3f"

,vce) ;

write_ftext_{(xwidth/2-40,}yheight-15, 1, 0, temp); } }

write_ftext(1,yheight-15, 1,0, "Up-Down Arrow or _Enter"); sprintf_(temp,"Temp=%5. If _C",te-273.0);

write_ftext_(xwidth-120,yheight-15, 1,0, temp); sprintf_(lab, "%3. If",xminl) ;

write_ftext₍40_,27*yheight/30, 1,0,lab);

sprintf_(lab, "%3. If

"

,xmaxl);

write_ftext₍halfx-30,27*yheight/30,1,0,lab) ;

write_ftext₍1,26*yheight/30,1,0, "₁₀"

) ;

write_ftext₍1,55,1,0, "₁₀"

);

write_ftext (xwidth-25,halfy/2+40,0,1,

"Beta"

) ; write_ftext(2*xwidth/3,25, 1,0, "Beta vs _Ic");

if(iwhich==-l)

write_ftext₍2*xwidth/3,27*yheight/30, 1,0, "Ie (Amps) "

) ;

write_ftext₍2*xwidth/3 27*yheight/30 1 0 "Ic (Amps₎"

xmin2=lE21;

xmax2=-lE21;

ymin2=xmin2 ; ymax2=xmax2 ;

for₍i=0_;i<=icount_{; i++)}

{if₍ic_[i_]<xmin2_{) xmin2=ic[i];}

if₍ic_[i_]>xmax2_{) xmax2=ic[i];}

if_{(beta[0] [i]<ymin2)}

ymin2=beta[0] [i] ;

if_{(beta[0] [i]>ymax2) ymax2=beta[0}

] [i];

newminmax₍&xmax2_,&xmin2 _);

newminmax₍&ymax2_,&ymin2_{) ;}

if (ymax2-ymin2>l. 0)

sprintf_(lab,"%4._Of",ymin2);

else

sprintf_(lab,"%5. _{If",ymin2) ;}

write_ftext(xwidth-36,25*yheight/29,l,0,lab);

if (ymax2-ymin2>l. 0)

sprintf_(lab, "%4._Of",ymax2);

else

sprintf₍lab_, "

%5. If

"

,ymax2) ;

write_ftext₍xwidth-36,40,1,0,lab) ;

writ e_ftext₍halfx+10_,27*yheight/30,1,0,

"

10"

) ;

write_ftext (xwidth-65_,27*yheight/30, 1,0,

"₁₀" ) ;

if(_setfont₍ "t'

tms rmn hl0w5b"₎<0₎

{_outtext( "can't set font" _);

getchar_{( ) ; }}

if_{(_getfontinfo(&fi) )}

{ _outtext("Can't get font info");

exit₍ 1_{) ;}

}

sprintf_(lab,"%3._{2d", (int)yminl);}

write_ftext (14,27 *yheight/32, 1,0,lab) ;

sprintf_{(lab, "%3.2d", (int)ymaxl);}

write_ftext(14,45,1,0, lab₎;

sprintf_{(lab, "%3.2d", (int)xmin2);}

write_ftext₍halfx+25,halfy+5,1,0,lab) ;

sprintf_{(lab, "%3.2d", (int)xmax2);}

write_ftext_(xwidth-50,halfy+5, 1,0,lab) ;

if(_setfont₍ "t'

tms rmn hl5wl0b" ₎<0₎

{_outtext("can't set _font");

getchar_{( ); }}

if(_getfontinfo₍&fi_{) )}

sprintf_{( temp,"%3s=%+l0}

. 2e"_,sp[chose-1] _,f[chose] ) _;

else

sprintf_(temp, "%2s=%+10.2e"

,sp[chose-l] ,f[chose]);

(1,1,rows_,cols_);

(0,0,xwidth-1_,yheight-1_{) ;}

_setwindow(TRUE,0_.0,0.0, (double) (xwidth-1)

, (double)

(yheight-i));

write_text(rows-l,cols/2-4, " ");

write_ftext_{(xwidth/2-_getgtextextent( temp )/2}

,yheight-32, 1,0,

temp) ; }

_settextwindow(l,1, rows, cols/2);

(40,45,halfx-10_,halfy);

(TRUE,xminl,yminl,xmaxl,ymaxl) ; if_(new==0)

{_setcolor(1) ;

(_GBORDER,xminl_,ymaxl_,xmaxl,yminl) ;

(11);

_setcolor(2);

if_(gumdata)

plotpix₍2_{,idata,vdata,}xmaxl-xminl,ymaxl-yminl,pixcol,0) ;

}

plot₍2_,icount,ii,v,xminl,xmaxl,yminl,ymaxl,new,linecol,

,0,1);

_settextwindow(1,cols/2+1, rows, cols) ;

/* _20-45 */

_setviewport(halfx+10,45,xwidth-40,halfy);

(TRUE,xmin2,ymin2,xmax2,ymax2) ;

if(new==0₎

{_setcolor(1) ;

tangle_w₍ ,xmin2,ymax2,xmax2,ymin2) ;

if_(gumdata)

plotpix₍1,idata,icdata,xmax2-xmin2,ymax2-ymin2,pixcol,2) ;

}

plot₍ 1,icount,beta,ic,xmin2,xmax2,ymin2,ymax2,new,linecol, XOR,1,0);

while₍ TRUE ₎

{ switch₍ GetKey(CLEAR_WAIT) ) { case ENTER:

if(type==l)

mnuchoice_[0]="NPN"

;

else

mnuchoice_[0]="PNP"

;

mnuchoice_[ 1_]="Forward" ;

else

mnuchoice_[1_]="

Inverse"

;

if_(vbc==0)

strcpy(temp,"Vce=Vbe" ) ;

else

sprintf_{(temp, "Vce=%6.3f",vce) ;} mnuchoice_[2_{]=strdup(temp) ;}

sprintf_(temp, "Vbestart=%6. 3f",vstart) ;

mnuchoice_[3_{]=strdup(temp) ;}

sprintf(temp,"

Vbestop=%6.3_{f",vstop) ;}

mnuchoice_[4_{]=strdup(temp) ;}

sprintf_(temp,"Vbestep=%6.3f"

,vstep) ; mnuchoice_[5_{]=strdup( temp ) ;}

mnuchoice[6]="Done"; if_(vbc==0)

strcpy(temp,"Vec=Vbe"

) ;

else

sprintf_(temp,"Vec=%6.3f"

,vce) ; mnuchoice_[7_{]=strdup( temp )} ;

sprintf_(temp, "Vbcstart=%6.3f"

,vstart) ; mnuchoice_[8_{]=strdup( temp ) ;}

sprintf_(temp, "Vbcstop=%6.3f"

,vstop) ; mnuchoice_[9_{]=strdup( temp ) ;}

sprintf_(temp, "Vbcstep=%6.3f"

,vstep) ; mnuchoice_[ 10_{]=strdup(temp);}

if_(iwhich==-l) for(i=2;i<6;i++)

{strcpy( temp,mnuchoice[i] ) ; mnuchoice_[i_]=mnuchoice_[i+5_] ;

mnuchoice_[i+5_{]=strdup( temp )} ; }

getgo(7,&chose,&tip) ;

switch_(tip)

{ case 0:

/* _{parameter chosen */}

new=_{1 ;}

break; case 1:

/* _{replot chosen */}

new=0;

goto start2;

break;

case 2:

_settextwindow(1,cols/2+1,rows,cols) ;

(halfx+10,45,xwidth-40,halfy) ; (TRUE_,xmin2,ymin2,xmax2,ymax2) ;

plotpix₍ 1,idata,icdata,xmax2-xmin2,ymax2-ymin2,pixcol,2) ;

new=_{1 ;}

break;

case 3:

/* _{increment chosen}

*/

if₍incr<=0₎incr=. 1 ;

if₍incr>=l₎incr=

. 9 ;

new=l;

break; case 4:

if(vbc==0)

vce=0.0;

if₍strcmpi₍oltype_,mnuchoice_[0_{] )} !=0₎

{strcpy(oltype_,mnuchoice_[0_{] )} ;

vidflag=TRUE; }

if₍iwhich!=olwhich₎

{olwhich=_iwhich

;

vidflag=TRUE; } for(i=2;i<6;i++)

{j=2;

strcpy( temp,mnuchoice[i] ) ;

while_{( (temp[}j] !='=' )&&( j<strlen(temp) ) )

j++;

strncpy(temp2,temp+]+l,20) ; if(i==2 && strlen(temp2) !=0)

{if(strlwr(temp2)=="vbe"| |

strlwr(temp2)=="vbc" )

val=0.0;

else

val=atof₍temp2) ; if_(val!=vce)

{vce=val;

vidflag=TRUE;

if (vce==0.0)

vbc=0;

else

vbc=l;

}

if(i==3 && (val=atof(temp2)) !=0 && vstart!=val)

{vstart =val;

vidflag=TRUE;}

if(i==4 && (val=atof(temp2)) !=0 && vstop!=val)

{vstop=val;

vidflag=TRUE;}

{vstep=val;

vidflag=TRUE; } }

if_(vidflag) {new=0;

setvid_{( )} ; goto _{start; }}

break;

case 5: iwhich=l;

olwhich=l; return;

break;

}

break;

case U_DN:

f_[chose_]=f_[chose_]-f_[chose_{]*incr ;}

new=l;

/* _20-45

*/

(halfx+10_,45,xwidth-40,halfy) ; (TRUE,xmin2,ymin2,xmax2,ymax2) ;

plot₍ 1_,icount,beta,ic,xmin2,xmax2,ymin2,ymax2,new,linecol, XOR,1,0);

/*

20-45*/

(40,45,halfx-10_{,halfy) ;}

(TRUE,xminl,yminl,xmaxl,ymaxl) ;

plot₍2,icount,ii,v,xminl,xmaxl,yminl,ymaxl,new,linecol,

,0,1);

goto starts-break;

case U_UP:

f_[chose_]=f_[chose_]+f_[chose_{]*incr ;}

new=l;

/*20-45*/

(halfx+10,45,xwidth-40,halfy) ; (TRUE,xmin2,ymin2,xmax2,ymax2) ;

plot₍ 1,icount,beta,ic,xmin2,xmax2,ymin2,ymax2,new,linecol,

XOR,1,0);

/*20-45*/

(40,45,halfx-10,halfy) ;

} }

return;

}

/* _Ic-Vce

modelling segment _*/

void _{Icvce( )}

{

int _{xwidth, yheight, cols, rows,halfx,halfy, jtencount, icount;}

double xminl,xmaxl,yminl,ymaxl,vstart,vstep,vstop;

double ii_[3_{] [}100_{] ,}v_[100_] ,istart=50E-6;

double _{istep=50E-6,ib[5] ,val;} double _ymin2,ymax2;

char _{lab[4],temp[20],temp2[20];}

int _{i, j,k,rowMid, colMid,tip;} static int _vidflag;

int _{chose=0,olwhich=l;}

int _{new=0,numi,num;}

short _{linecol=10,pixcol=12;}

kind _=2; /* _tells

rest of program call comes from IC-Vce

*/

_getvideoconfig(&vc );

rowMid =

vc.numtextrows / 2; colMid =

vc.numtextcols _{/ 2;} xwidth=vc. numxpixels;

yheight=vc. numypixels;

hal fx=xwidth_;

halfy=7*yheight/8; cols=vc. numtextcols;

rows=vc. numtextrows;

vstart=0. 0 ;

vstop=l._0; vstep=0. 2 ;

numi=2;

start : num=numi_;

vidflag=FALSE;

for( j=0; j<numi; j++)

{icount=-l;

bi=istart+₍double_)j*istep;

ib[j]=bi;

for₍vce=vstart; vce<=vstop ;vce+=vstep) { Spice();

ii[ j] [++icount]=type*ci;

v_[icount_]=type*_vce ;

} }

time=0 ;

start2:if₍new==0₎

xmaxl=-lE21; yminl=xminl; ymaxl=xmaxl;

for₍j=0;j<numi_{; j++)}

for₍i=0;i<=icount; i++)

{ if_{(ii[j] [i]<yminl)} yminl=ii_{[j] [}i_] ;

if_{(ii[j] [i]>ymaxl)}

ymaxl=ii[j] [i] ; if(j==0)

{if_{(v[i]<xminl) xminl=v[i];}

if_{(v[i]>xmaxl) xmaxl=v[i];}

} }

newminmax₍&xmaxl,&xminl) ;

newminmax₍Symaxl,&yminl) ;

_clearscreen( );

if_(iwhich==l)

{write_ftext(xwidth/2-70,25, 1,0, "Collector Current vs

Vce");

write_ftext (xwidth/2-25 , 2 7*yheight/30 , 1, 0, "Vce

(Volts)"); }

else

{write_ftext(xwidth/2-70,25, 1,0, " _{Emitter Current vs}

Vce");

write_ftext (xwidth/2-25, 2 7*yheight/30 , 1, 0 , "Vec

(Volts)"); }

if(type==-l)

{val=ymaxl;

ymaxl=yminl; yminl=val; }

if_(fabs(ymaxl_)<1.0e-9)

{if_(iwhich==l)

strcpy( temp, "Ic pAmps");

else

strcpy( temp, "Ie pAmps"); ymax2=ymaxl*1.0el2;

ymin2=yminl*l. 0el2 ;

goto next; }

else if_(fabs(ymaxl_)<1.0e-6)

{if(iwhich==l)

strcpy(temp, "Ic nAmps");

else

strcpy(temp, "Ie nAmps");

ymax2=ymaxl*₁

. 0e9 ;

ymin2=yminl*₁