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SM2MHELP
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1992-09-29
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--- SPICEMOD GENERAL HELP ---
SPICEMOD quickly converts data book parameters into SPICE parameters.
Entering only the device type and maximum voltage and current ratings
will produce a usable model as all other parameters are scaled from
them. Naturally, the more data entered, the more exact the model.
===========================================================================
THIS TRIAL VERSION OF SPICEMOD ALLOWS CHANGES FOR ONLY THE FIRST FIVE
DEVICE PARAMETERS. IT DOES NOT INCLUDE THE MORE COMPLEX SUBCIRCUIT
DEVICES. IT DOES NOT PERMIT SAVING MODELS OR EDITING THE MODEL FILES.
===========================================================================
Select the device to be modeled from the MENU:
DIODE - Use for signal or power diodes.
ZENER DIODE - Use for zener Diodes.
BIPOLAR JUNCTION TRANSISTOR - Low and medium power transistors
JUNCTION FET - Signal junction FET
MOS-FET - Four terminal signal MOS-FET
SUBCIRCUIT DEVICES - Switches to a SUBCIRCUIT menu for more complex
macro models (Power Transistor, Darlington, Power MOS-FET, IGBT and
SCR subcircuits).
VIEW MODEL FILE - Permits easy viewing of the model file without
danger of changing it.
EDIT MODEL FILE - Allows editing of the model file with your
favorite editor with automatic return to SPICEMOD.
Enter test or data book information in the list:
Limit the name of the device to eight (8) characters as some
versions of SPICE will not recognize more.
Skip any unknown values. They will be estimated from the
known information that you enter. Any data you enter will be
kept fixed, and highlighted.
More data will result in more accurate SPICE model parameters.
Remember, you control the type of model that you generate. High
or low limit models can be developed by entering high or low
limit data in separate runs. To make a nominal model, enter
all nominal values. To make a slow model enter maximum capaci-
tances and rise and fall times, and minimum Ft.
Be careful of the type of data you are copying from the data
book (Min, Max, or Typical)! Note that data book curves do not
always represent nominal devices.
You will be allowed to save the model to a file of your choice
as you exit the device model if you have entered data. These
files are in the proper format for "*INCLUDE" files. If you want
to look at the file use "View Model File". To edit these files,
use your favorite editor in the non-document or text mode (don't use
WordStar(R) or WordPerfect(R) in the document mode or odd characters
will be generated which cause SPICE problems). IS_ED works fine for
this purpose.
You may want to make special model files with special data:
NOMINAL .LIB (nominal parameters)
HIGAIN .LIB (high gain parameters)
LOGAIN .LIB (low gain parameters)
SLOW .LIB (maximum delay and capacitances)
FAST .LIB (minimum delay and capacitances)
TI-MODEL.LIB (TI device models)
M-MODEL .LIB (Motorola device models)
NOTE: This program is intended to generate custom models and manage
small libraries of frequently used models.
Because all data is kept in memory, this program can not fully
support files with thousands of models. When working with these
large files, add the new models without attempting to look at
the files or replace old models. Use your favorite editor to
view or eliminate old models in large files.
--- SPICE DIODE MODEL PARAMETERS ---
INPUT DATA:
-------------------------------------------------------------------------------
.MODEL Name must be no more than eight characters and is used to find
this model in the model library.
Type = Germanium, Silicon, or Gallium Arsenide (use first two letters)
IF = Rated Continuous Forward Current (must be entered)
Note: All data below this point will be estimated if not entered:
IM = A current about 1/10 of Rated Current
VM = Forward Voltage Drop at IM (used to estimate IS)
IL = A current about 1/100 of Rated Current
VL = Forward Voltage Drop at IL (used with VM to estimate N)
IH = A High Current (for best accuracy choose the point where the
temperature curves cross to eliminate temperature drift errors)
VH = Forward Voltage Drop at IH (used to estimate RS)
VR = DC Blocking Voltage (used to calculate BV)
IR = Maximum Reverse Current at VR (used for IBV, reduces BV by RS * IZ)
CJ = Reverse Biased Junction Capacitance (used to estimate CJO)
VJ = Voltage at which CJ is measured (for best accuracy use a reverse
voltage near zero)
trr = Reverse Recovery Time (IR = IF at rated current) (used for TT)
OUTPUT PARAMETERS:
-------------------------------------------------------------------------------
IS = Saturation Current (adjusts for junction area and doping level)
(combines with N to determine forward voltage drop)
RS = Diode Ohmic Series Resistance (main factor in determining
forward voltage drop at high currents)
N = Emission Coefficient (slope of forward voltage curve at low
currents) (ranges from 1.0 to 2.2, typically 1.7)
BV = Reverse Breakdown Voltage (BV = VR - IBV * RS)
IBV = Current at Reverse Breakdown (same as IR)
CJO = Zero Bias Junction Capacitance
VJ = Junction Potential (typical .75)
M = Grading Coefficient (.3 for a linearly graded junction, .5 for
an abrubt junction)
TT = Transit Time (estimate as 1.44 * TRR)
DIODE VOLTAGE EQUATION:
V = I*RS + N*T*(k/q) * ln(I/IS + 1)
where:
V = Diode Voltage
I = Diode Current
ln = Natural Logarithm
T = Temperature in Degrees Kelvin (degrees C + 273.2)
k = Boltzmann's Constant (1.38E-23)
q = Electron Charge (1.6E-19)
JUNCTION CAPACITANCE EQUATION (REVERSE BIAS):
C = CJO / (1 - V/VJ)^M
where:
C = Junction Capacitance
V = Diode Voltage
--- SPICE ZENER DIODE MODEL PARAMETERS ---
This model uses a SPICE diode to model a Zener diode. BV, IBV and RS are
adjusted to model the reverse (zener) operation, and IS and N are used
to model the forward diode operation. The fit will be good at the points
that have been entered as input data in the zener region. The forward
voltage at high currents will be too high due to adjusting RS for better
zener modelling. A macro model (.SUBCKT) must be used for more accurate
forward characteristics modelling and to model reverse voltage temperature
characteristics.
INPUT DATA:
-------------------------------------------------------------------------------
Model Name: Use an eight-character name to identify the model.
VZ = Zener Voltage (used to calculate BV, IS and CJ)
IZT = Zener Test Current (used for IBV)
ZZT = Zener Impedance at IZT (used to estimate RS and adjust BV)
IF = Rated Forward Current
VF = Forward Voltage at IF (used with IF to estimate IS)
IL = A current about 1/10 of Rated Forward Current
VL = Forward Voltage Drop at IL (used with IL to estimate IS)
CJ = Reverse Biased Junction Capacitance (used to estimate CJO)
VJ = Voltage at which CJ is measured (usually VZ)
trr = Reverse Recovery Time (IR = IF at rated current) (used for TT)
OUTPUT PARAMETERS:
-------------------------------------------------------------------------------
IS = Saturation Current (adjusts for junction area and doping level)
(combines with N to determine forward voltage drop)
RS = Diode Ohmic Series Resistance (main factor in determining
zener impedance at high currents)
N = Emission Coefficient (slope of forward voltage curve at low
currents)
BV = Reverse Breakdown Voltage (adjusted for RS and IBV)
IBV = Current at Reverse Breakdown (same as IZT)
CJO = Zero Bias Junction Capacitance
VJ = Junction Potential (typical .75)
M = Grading Coefficient (.3 for a linearly graded junction, .5 for
an abrubt junction)
TT = Transit Time (estimate as 1.44 * TRR)
DIODE VOLTAGE EQUATIONS:
-------------------------------------------------------------------------------
In the forward region:
VF = IF*RS + N*Vt*ln(IF/IS + 1)
In the zener operating region:
VR = BV + IR*RS + Vt*ln(IR/IBV)
where:
VF = Diode Forward Voltage
IF = Diode Forward Current
VR = Diode Reverse Voltage
IR = Diode Reverse Current
Vt = T*k/q (= .0259 volts at room temperature)
T = Temperature in Degrees Kelvin (degrees C + 273.2)
k = Boltzmann's Constant (1.38E-23)
q = Electron Charge (1.6E-19)
JUNCTION CAPACITANCE EQUATION (REVERSE BIAS):
C = CJO / (1 - V/VJ)^M
where:
C = Junction Capacitance
V = Diode Voltage
--- SPICE BIPOLAR TRANSISTOR PARAMETERS ---
INPUT DATA:
------------------------------------------------------------------------------
.MODEL Name - Used to identify the model in the library (eight
characters maximum).
Type = Use a minimum of three letters to identify the type.
VCEO = Rated Collector-Emitter Breakdown Voltage (used to es-
timate VAF) (must be entered)
VEBO = Maximum Emitter-Base Voltage (used to estimate VAR)
ICmax = Rated Continuous Collector Current (must be entered)
(Scales all values below:)
Note: All data below this point will be estimated if not entered:
hFE = Peak Point of Foreward Current Gain (used for BF)
IH = hFE Curve High Current 50% Fall-Off Point (used for IKF)
IL = hFE Curve Low Current 50% Fall-Off Point (used for ISE, NE)
(must be less than IH/100 or would cause very large BF)
VCE(SAT) = Collector Saturation Voltage (used for RC, RE, and RB)
at IC = Current for VCE test (near maximum current)
VBE(ON) = Base Voltage for forced beta of 10 (used to estimate IS)
Note: Don't use Max value unless you want a Max VBE model, use the
typical value from the VBE curves.
at IC = Collector Current for VBE(ON) (use forced beta of 10 at a
low current, ICmax / 25)
fT = Maximum Gain-Bandwidth Product (used to estimate TF)
ts = Storage Time at same current as maximum fT (used to estimate TR)
COB = Output Capacitance (Collector-Base) (used to estimate CJC)
VCB = Voltage for COB Measurement
CIB = Input Capacitance (Emitter-Base) (used to estimate CJE)
VEB = Voltage for CIB Measurement (use a reverse voltage near
zero for best accuuracy)
OUTPUT PARAMETERS:
These parameters control normal operation of the transistor:
------------------------------------------------------------------------------
IS = Saturation Current (adjusts for junction area)
NF = Forward Emission Coefficient (slope of VBE at low current)
BF = Maximum Forward Beta (before reduction at high current by
IKF and at low current by ISE, NE)
VAF = Forward Early Voltage (Output Impedance (slope of collector
family curves) times collector current)
IKF = High Current Beta Roll Off (current where beta = .5 Max.)
ISE = B-E Leakage Saturation Current (shunts B-E current at low
currents to cause beta roll-off)
NE = B-E Leakage Emission Coefficient (determines slope of beta
fall-off at low currents - must be greater than NF)
RE = Emitter Series Resistance (You can save a node by leaving
this parameter out, but VBE and VCE will not be accurate at
high collector currents.)
RB = Base Series Resistance (You can save a node by leaving this
parameter out, but VBE at very high base currents will be
under estimated.)
RC = Collector Series Resistance (You can save a node by leaving
this out and adding RC to RE to give reasonable estimates of
both VBEsat and VCEsat.)
The following parameters are important when the B-C junction
becomes forward biased as in VCEsat or when the transistor is
operated with emitter and collector reversed:
------------------------------------------------------------------------------
BR = Maximum Reverse Beta (before reduction at high current by
IKR and at low current by ISC, NC)
NR = Reverse Emission Coefficient (slope of VBC at low current)
(Ratio of NF to NR sets offset of VCEsat at low current.)
IKR = High Current Reverse Beta Roll Off (current where reverse
beta = .5 Max.)
VAR = Reverse Early Voltage (Output Impedance (slope of reverse
family curves) times collector current)
ISC = B-C Leakage Saturation Current (shunts B-C current at low
currents to cause reverse beta roll-off)
NC = B-C Leakage Emission Coefficient (determines slope of re-
verse beta roll off at low currents - must be greater than
NR)
XTB = Forward and Reverse Beta Temperature Coefficient (fixed at 1.5)
The following parameters control the performance of the transistor
at high frequencies:
------------------------------------------------------------------------------
CJE = B-E Zero Bias Depletion Capacitance (CIB adjusted for voltage)
VJE = B-E Junction Built-in Potential (1.1 for this abrupt junction)
MJE = B-E Capacitance Exponential Factor (.5 for this abrupt junction)
CJC = B-C Zero Bias Depletion Capacitance (COB adjusted for voltage)
VJC = B-C Junction Built-in Potential (.3 for this graded junction)
MJC = B-C Capacitance Exponential Factor (.3 for this graded junction)
TF = Ideal Forward Transit Time (not Fall Time)
TR = Ideal Reverse Transit Time (not Rise Time)
Some useful equations follow:
------------------------------------------------------------------------------
Use this equation to find IS if you want to change NF:
IS = IC/(HFE * EXP(38.6 * VBE/NF))
(Use a low IC where RE and RB drops in VBE can be neglected.)
Use this equation to find ISE if you want to change NF or NE:
ISE = IS/BF * (IL/IS)^(1-NF/NE)
--- SPICE JUNCTION FIELD EFFECT TRANSISTOR HELP ---
INPUT DATA:
------------------------------------------------------------------------------
.MODEL Name - must be no more than eight characters and is used to find
the model in the model library.
Channel Type - can be "N" or "P".
Enhancement or Depletion Mode - Most J-FETs are depletion mode.
Enhancement Mode devices have no drain current at zero gate
voltage.
Depletion Mode devices require reverse bias on the gate to
cut off drain current.
(determines VGS(OFF) and VTO polarity)
V(BR)GSS = Rated Gate-Source Breakdown Voltage (used to estimate
IS) (must be entered)
ID = Maximum Drain Current (must be entered)
VGS(off) = Rated Gate-Source Cut-Off Voltage (used to estimate VTO)
(must be entered)
Note: All data below this point will be estimated if not entered:
IDSS = Zero-Gate-Voltage Drain Current (used to estimate BETA)
(not used for enhancement mode devices)
rDS(on) = Drain-to-Source ON-Resistance (used to estimate RD, RS)
Yfs = Forward Transfer Admittance (used for BETA)
This is similar to gFS (Forward Tranconductance) except
that it includes reactive components. The two are nearly
equal at low frequencies.
Ciss = Input Capacitance (used to estimate CGS)
Crss = Feedback Capacitance (used to estimate CGD, CGS)
OUTPUT PARAMETERS:
------------------------------------------------------------------------------
VTO = Gate Threshold Voltage
BETA = Transconductance
LAMBDA = Channel Length Modulation Parameter (slope of I vs VDS)
(similar to Early voltage in BJT) (output conductance in
saturation where VDS > VTO)
RD = Drain Ohmic Resistance
RS = Source Ohmic Resistance
IS = Gate Junction Saturation Current (adjusts for junction area)
(used for foreward biased gate current calculations)
The following parameters control the performance of the transistor
at high frequencies:
------------------------------------------------------------------------------
PB = Bulk (Gate) Junction Potential (used in junction capacitance
calculation)
M = Junction Grading Coefficient (fixed at .5)
CGS = Zero Bias G-S Junction Capacitance (Ciss - Crss adjusted for
test voltages)
CGD = Zero Bias G-D Junction Capacitance (Crss adjusted for VGD)
NOTE: The values calculated for CGS and CGD may seem large since they
are extrapolated to the zero-bias condition and SPICE has a fixed
value for the exponent (M) of .5, but results should be accurate
if the value you enter is close to your operating point. Don't
forget to enter the stray capacities of your real circuit in your
SPICE simulation circuit for best results.
EQUATIONS:
------------------------------------------------------------------------------
VGS < VTO: ID = 0 (Cutoff Region)
VDS < VGS-VTO: ID = -BETA*(1-LAMBDA*VDS)*(2*(VGS-VTO)+VDS) (Linear)
VDS > VGS-VTO: ID = -BETA*(1-LAMBDA*VDS)*(VGS-VTO)^2 (Saturation)
--- SPICE MOS FIELD EFFECT TRANSISTOR HELP ---
INPUT DATA:
------------------------------------------------------------------------------
.MODEL Name - must be no more than eight characters and is used to find
this model in the model library.
Channel Type - use "N" or "P". Determines bias polarities.
Enhancement or Depletion Mode - use "E" or "D".
Enhancement Mode devices have no drain current at zero gate
voltage.
Depletion Mode devices require reverse bias on the gate to
cut off drain current.
(determines VGS(th) and VTO polarity)
CAUTION: The values below assume the default W = 100U for channel width
and L = 100U for channel length. If W is changed, CGSO, CGDO,
and CGBO must be changed since they are multiplied by W.
(If W = 1 then multiply the CxxO values by .0001)
(If W or L is changed, multiply Yfs by L/W to adjust for KP
being multiplied by W/L in SPICE.)
V(BR)DSS = Maximum Drain-Source Breakdown Voltage (used to estimate
IS) (must be entered)
VGS(Th) = Rated Gate Threshold Voltage (used to estimate VTO)
(must be entered - polarity automatically selected)
ID = Maximum Drain Current (must be entered)
(Scales all values below:)
Note: All data below this point will be estimated if not entered:
rDS(on) = Drain-to-Source ON-Resistance (used to estimate RD, RS)
(Usually specified in the data book as max. Use a lower
value if you want nominal performance.)
Yfs = Forward Transfer Admittance (used for KP) - See CAUTION above.
This is similar to gFS (Forward Transconductance) except
that it includes reactive components. The two are nearly
equal at low frequencies.
Ciss = Input Capacitance (used to estimate CGBO)
(Measured at high VDS to minimize CBD) - See CAUTION above.
Crss = Reverse Transfer Capacitance (used to estimate CGDO, CGSO)
(usually measured at VDS = 0) - See CAUTION above.
Cd(sub) = Drain-Substrate Capacitance (used to estimate CBS, CBD)
VD(SUB) = Drain-Substrate Voltage for Cd(sub) measurement
OUTPUT PARAMETERS:
------------------------------------------------------------------------------
NOTE: The MOS-FET model parameters developed in this program are for
discrete devices and use the default size parameters (L=100U W=100U)
after the model name.
LEVEL=1 invokes the Shichman-Hodges model (default)
This is best for long channel (high voltage) devices.
It is used here to more easily match data book velues.
LEVEL=2 invokes the "MOS2" model described in U of C
Berkeley Memo # UCB/ERL M80/7 "The Simulation of MOS
Integrated Circuits Using SPICE2" section 2.2, and is
best for discrete MOS-FETs.
LEVEL=3 invokes the semi-emperical model described in section 4
of the same publication and is better for narrow gate
(newer low voltage) devices.
VTO = Zero Bias Threshold Voltage
KP = Intrinsic Transconductance Parameter (multiplied by W/L)
GAMMA = Bulk Threshold Parameter (effect of backgate bias on VTO)
(defaults to .5)
PHI = Surface Potential (defaults to .6)
LAMBDA = Channel Length Modulation Parameter (slope of I vs VDS)
(similar to Early voltage in BJT) (output conductance in
saturation where VDS > VTO) (MOS1 and MOS2 only)
RD = Drain Ohmic Resistance
RS = Source Ohmic Resistance
IS = Bulk Junction Saturation Current (adjusts for junction area)
(total reverse current of drain and source junctions)
The following parameters control the performance of the transistor
at high frequencies:
------------------------------------------------------------------------------
CBD = Zero Bias Bulk-Drain Junction Capacitance
CBS = Zero Bias Bulk-Source Junction Capacitance (This has no effect
when the substrate is connected to the source.)
PB = Bulk Junction Potential (use the default value of .8)
MJ = Bulk Junction Grading Coefficient (use the default value of .5)
NOTE: The next three parameters assume that W = 100U (the default value).
(These MOS capacitor values are not voltage dependent.)
CGSO = Gate-Source Overlap Capacitance (multiplied by W) (assumed to
be 1.2 times CGDO)
CGDO = Gate-Drain Overlap Capacitance (multiplied by W) (equal to
Crss corrected for gate width W)
CGBO = Gate-Bulk Overlap Capacitance (multiplied by W) (equal to
Ciss - CGDO - CGSO or Ciss - 2.2 * Crss, corrected for W)
EQUATIONS:
------------------------------------------------------------------------------
when VDS > 0 and: (Forward Conduction)
VGS < VTO: ID = 0 (Cutoff Region)
VDS < VGS-VTO: ID = KP*W/L*(1+LAMBDA*VDS)*VDS*(2*(VGS-VTE)-VDS) (Linear)
VDS > VGS-VTO: ID = KP*W/L*(1+LAMBDA*VDS)*(VGS-VTE)^2 (Saturation)
where:
VTE = VTO+GAMMA*(SQR(PHI-VBS)-SQR(PHI))
when VDS < 0 and: (Reverse Conduction)
VGS < VTO: ID = 0 (Cutoff Region)
-VDS < VGD-VTO: ID = -KP*W/L*(1-LAMBDA*VDS)*VDS*(2*(VGD-VTE)+VDS)(Linear)
-VDS > VGD-VTO: ID = -KP*W/L*(1-LAMBDA*VDS)*(VGD-VTE)^2 (Saturation)
where:
VTE = VTO+GAMMA*(SQR(PHI-VBD)-SQR(PHI))