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Updated documentation afer resistor model update.

This commit is contained in:
pnenzi 2003-09-20 20:18:25 +00:00
parent bec68b1559
commit 5e124c6a60
3 changed files with 234 additions and 70 deletions
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12
ChangeLog
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@ -1,6 +1,16 @@
2003-09-20 Paolo Nenzi <p.nenzi@ieee.org>
* src/spicelib/devices/res/*, src/spicelib/analysis/nevalsrc.c,
doc/ngspice.texi, DEVICES: Added new features to resistors:
flicker noise, tempereature difference with the rest of the
circuit, noiseless resistors. The implementation of dtemp
required a change in the nevalsrc.c file in the function that
computes the noise densities. Updated documentation.
2003-09-18 Paolo Nenzi <p.nenzi@ieee.org>
* src/spicelib/frontend/dctrcv.c: Corrected temperature sweep.
* src/spicelib/analysis/dctrcv.c: Corrected temperature sweep.
Initial temp was the circuit temperature and not the start
value in the input line. There was a missing call to CKTtemp().

52
DEVICES
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@ -10,11 +10,29 @@ This file it is useful in writing ngspice documentation.
************************* Linear devices ********************************
***************************************************************************
CAP - Capacitor
Initial Release
CAP - Capacitor
Initial Release
IND - Inductor
Initial Release
IND - Inductor
Initial Release
RES - Simple linear resistor
Initial Release.
Ver: N/A
Class: R
Level: 1 (and only)
Status:
Enhancements over the original model:
- Parallel Multiplier
- Different value for ac analysis
- Temperature difference from circuit temperature
- Noiseless resistor
- Flicker noise
- Preliminary technology scaling support
- Xspice extensions
- Cider extensions
RES - Resistor
This is a modified version of the spice3 resistance model. This model
@ -226,7 +244,7 @@ BSIM3v2 - BSIM model level 3
BSIM4 - BSIM model level 4 (0.18 um)
Initial Release.
Ver: 4.2.1 (Updated in rewor 14)
Ver: 4.2.1 (Updated in rework 14)
Class: M
Level: 14
Status: TO BE TESTED
@ -239,7 +257,27 @@ BSIM4 - BSIM model level 4 (0.18 um)
*) Rework 14: Updated to 4.21 YET UNTESTED.
HiSIM - Hiroshima-university STARC IGFET Model
Initial Release.
Ver: 1.2.0
Class: M
Level: TBD
Status: TO BE TESTED
This is the HiSIM model available from Hiroshima University
(Ultra-Small Device Engineering Laboratory)
Web site:
http://home.hiroshima-u.ac.jp/usdl/HiSIM.shtml
http://www.starc.or.jp/kaihatu/pdgr/hisim/index.html
Enhancements over the original model:
- Parallel Multiplier
- Xspice extensions
- Cider extensions
- Copynodeset (?)
***************************************************************************
***************************** SOI Devices ****************************
***************************************************************************
@ -320,4 +358,4 @@ EKV - EKV model
Web site at:
http://legwww.epfl.ch/ekv/

240
doc/ngspice.texi
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@ -1770,10 +1770,10 @@ in the direction of voltage drop).
General form:
@example
RXXXXXXX N1 N2 VALUE <ac=val> <m=val> <scale=val>
RXXXXXXX n+ n- value <ac=val> <m=val> <scale=val> <dtemp = val>
+ <noisy = 0|1>
@end example
Examples:
@example
@ -1783,23 +1783,79 @@ in the direction of voltage drop).
RL 1 4 2K m=2
@end example
Ngspice has a fairly complex model for resistors. It can simulate both
discrete and semiconductor resistors. Semiconductor resistors in ngspice
means: resistors described by geometrical parameters. So, do not expect
detailed modeling of semiconductor effects.
N1 and N2 are the two element nodes. VALUE is the resistance (in ohms)
and may be positive or negative but not zero. It is possible to specify
a different resistance value for ac calculations, using the "ac"
parameter. The value of ac resistance must not be zero. If you do not
specify the "ac" parameter, it will be defaulted to VALUE.
@option{n+} and @option{n-} are the two element nodes, @option{value} is the
resistance (in ohms) and may be positive or negative but not zero. If you
need to simulate very small resistors (0.001 Ohm or less) , you should use
CCVS (transresistance), it is less efficient but improves numerical
accuracy (a small resistance is a large conductance).
Ngspice can assign a resistor instance a different value for AC analysis,
specified using the @option{ac} keyword. This value must not be zero as
described above. The AC resistance is used in AC analysis only (not Pole-Zero
nor noise). If you do not specify the @option{ac} parameter, it is defaulted
to @option{value}.
The "m" parameter is the "multiplication factor" and scale is the "scale"
factor:
Resistance = Resistance * Scale / M
Setting m to "val" is like putting m equal resistance in parallel.
The "scale" parameter let the designer to choose a different scale
for elements.
The @option{m} parameter is the "multiplication factor", and can be used to
simulate "m" instances of the same kind in parallel. This parameter affects
all analyses.
Note: ac parameter can be considered "safe" since rework-11
Scale parameter is not applied to l,w and other geometric
parameters.
The @option{scale} keyword let the designer choose a different scale for
elements. This option is not yet very useful, it will fully implemented in the
future to perform technology scaling. At present is here as a work in progress.
The operating temperature of instances can be changed using the @option{dtemp}
keyword. Ngspice simulates the circuit with all components at the same single
temperature (the circuit temperature). To adjust the temperature of a resistor
instance you can define its temperature difference from the rest of the
circuit using @option{dtemp}.
If you want to simulate temperature dependence of a resistor, you need to
specify its temperature coefficients, using a @command{.model} line, like in the
example below:
@example
RE1 1 2 700 std dtemp=5
.MODEL std tc1=0.001
@end example
Instance temperature is useful even if resistance does not varies with it, since
the thermal noise generated by a resistor depends on its absolute temperature.
Resistors in ngspice generates two different noises: thermal and flicker. While
thermal noise is always generated in the resistor, to add a flicker noise source
you have to add a @command{.model} card defining the flicker noise parameters.
It is possible to simulate resistors that do not generate any kind of noise
using the @option{noisy} keyword and assigning zero to it, as in the
following example:
@example
Rmd 134 57 1.5k noisy=0
@end example
Ngspice calculates the nominal resistance as described below:
@tex
$$
R_{nom} = {{{\rm VALUE} * {\rm scale}} \over m}
$$
$$
R_{acnom} = {{{\rm ac} * {\rm scale}} \over m}
$$
@end tex
@ifnottex
@example
Rnom = value * scale / m
Racnom = ac * scale / m
@end example
@end ifnottex
If you are interested in temperature effects or noise equations, read the
following section on semiconductor resistors.
@node Semiconductor Resistors, Semiconductor Resistor Model (R), Resistors, Elementary Devices
@subsection Semiconductor Resistors
@ -1807,8 +1863,8 @@ Note: ac parameter can be considered "safe" since rework-11
General form:
@example
RXXXXXXX N1 N2 <VALUE> <MNAME> <L=LENGTH> <W=WIDTH> <TEMP=T>
m=<val> <ac=val> <scale=val>
RXXXXXXX n+ n- <value> <mname> <l=lenght> <w=width> <temp=t>
+ <dtemp=val> m=<val> <ac=val> <scale=val> <noisy = 0|1>
@end example
@ -1819,20 +1875,20 @@ Note: ac parameter can be considered "safe" since rework-11
RMOD 3 7 RMODEL L=10u W=1u
@end example
This is the more general form of the resistor presented before (@pxref{Resistors})
and allows the modeling of temperature effects and for the calculation of the
actual resistance value from strictly geometric information and the
specifications of the process. If @option{value} is specified, it overrides
the geometric information and defines the resistance. If @option{mname} is
specified, then the resistance may be calculated from the process information
in the model @option{mname} and the given @option{lenght} and @option{width}.
If @option{value} is not specified, then @option{mname} and @option{lenght}
must be specified. If @option{width} is not specified, then it is taken
from the default width given in the model.
This is the more general form of the resistor presented in section
6.1, and allows the modeling of temperature effects and for the
calculation of the actual resistance value from strictly geometric
information and the specifications of the process. If VALUE is
specified, it overrides the geometric information and defines the
resistance. If MNAME is specified, then the resistance may be
calculated from the process information in the model MNAME and the
given LENGTH and WIDTH. If VALUE is not specified, then MNAME and
LENGTH must be specified. If WIDTH is not specified, then it is taken
from the default width given in the model. The (optional) TEMP value
is the temperature at which this device is to operate, and overrides
the temperature specification on the .OPTION control line.
The (optional) @option{temp} value is the temperature at which this device is
to operate, and overrides the temperature specification on the
@command{.option} control line and the value specified in @option{dtemp}.
@ -1845,63 +1901,92 @@ the resistance to be calculated from geometric information and to be
corrected for temperature. The parameters available are:
@multitable @columnfractions .15 .4 .2 .1 .1
@item name @tab parameter @tab units @tab default @tab example
@item TC1 @tab first order temperature coeff.
@tab Z/°C @tab 0.0
@item TC2 @tab second order temperature coeff.
@tab Z/°C@math{^2} @tab 0.0
@item RSH @tab sheet resistance
@tab Z/[] @tab - @tab 50
@item DEFW @tab default width
@tab meters @tab 1e-6 @tab 2e-6
@item name @tab parameter @tab units @tab default @tab example
@item TC1 @tab first order temperature coeff.
@tab Ohm/°C @tab 0.0
@item TC2 @tab second order temperature coeff.
@tab Ohm/°C@math{^2} @tab 0.0
@item RSH @tab sheet resistance
@tab Ohm/[] @tab - @tab 50
@item DEFW @tab default width
@tab meters @tab 1e-6 @tab 2e-6
@item NARROW @tab narrowing due to side etching
@tab meters @tab 0.0 @tab 1e-7
@tab meters @tab 0.0 @tab 1e-7
@item SHORT @tab shortening due to side etching
@tab meters @tab 0.0 @tab 1e-7
@item TNOM @tab parameter measurement temperature
@tab °C @tab 27 @tab 50
@tab meters @tab 0.0 @tab 1e-7
@item TNOM @tab parameter measurement temperature
@tab °C @tab 27 @tab 50
@item KF @tab flicker noise coefficient
@tab - @tab 0.0 @tab 5e-15
@item AF @tab flicker noise exponent
@tab - @tab 0.0 @tab 1.0
@end multitable
The sheet resistance is used with the narrowing parameter and L and W
from the resistor device to determine the nominal resistance by the
formula
The sheet resistance is used with the narrowing parameter and @option{l}
and @option{w} from the resistor device to determine the nominal resistance
by the formula
@tex
$$
R = {\rm RSH} {L - {\rm SHORT} \over W - {\rm NARROW}}
R_{nom} = {\rm rsh} {l - {\rm SHORT} \over w - {\rm NARROW}}
$$
@end tex
@ifnottex
@example
L - SHORT
R = RSH ----------
W - NARROW
L - SHORT
Rnom = RSH ----------
W - NARROW
@end example
@end ifnottex
DEFW is used to supply a default value for W if one is not specified for
the device. If either RSH or L is not specified, then the standard
default resistance value of 1k Z is used. TNOM is used to override the
circuit-wide value given on the .OPTIONS control line where the
parameters of this model have been measured at a different temperature.
After the nominal resistance is calculated, it is adjusted for
temperature by the formula:
@option{DEFW} is used to supply a default value for @option{w} if one is
not specified for the device. If either @option{RSH} or @option{L} is not
specified, then the standard default resistance value of 1k Ohm is used.
@option{TNOM} is used to override the circuit-wide value given on the
@command{.options} control line where the parameters of this model have
been measured at a different temperature.
After the nominal resistance is calculated, it is adjusted for temperature
by the formula:
@tex
$$
R(T) = R(T_0) \Bigl( 1 + TC_1 (T - T_0) + TC_2 (T-T_0)^2 \Bigr)
R(T) = R({\rm TNOM}) \Bigl( 1 + TC_1 (T - {\rm TNOM}) + TC_2 (T-{\rm TNOM})^2 \Bigr)
$$
where $R({\rm TNOM}) = R_{nom} \vert R_{acnom}$.
@end tex
@ifnottex
@example
2
R(T) = R(T ) [1 + TC (T - T ) + TC (T - T ) ]
0 1 0 2 0
2
R(T) = R(TNOM) [1 + TC (T - TNOM) + TC (T - TNOM) ]
1 2
where R(TNOM) = Rnom or Racnom
@end example
@end ifnottex
In the above formula, "T" represents the instance temperature, which can be
explicitly using the @option{temp} keyword or os calculated using the
circuit temperature and and @option{dtemp}, if present.
If both @option{temp} and @option{dtemp} are specified, the latter is ignored.
A small list of sheet resistances (in Ohm/[]) for conductors is shown below.
The table represents typical values for MOS processes in the 0.5 - 1 um
range. The table is taken from: @emph{N. Weste, K. Eshraghian - Principles of
CMOS VLSI Design 2nd Edition, Addison Wesley}.
@multitable @columnfractions .55 .15 .15 .15
@item Material @tab Min. @tab Typical @tab Max.
@item Intermetal (metal1 - metal2) @tab 0.005 @tab 0.007 @tab 0.1
@item Top-metal (metal 3) @tab 0.003 @tab 0.004 @tab 0.05
@item Polysilicon @tab 15 @tab 20 @tab 30
@item Silicide @tab 2 @tab 3 @tab 6
@item Diffusion(n+,p+) @tab 10 @tab 25 @tab 100
@item Silicided diffusion @tab 2 @tab 4 @tab 10
@item n-well @tab 1000 @tab 2000 @tab 5000
@end multitable
@node Capacitors, Semiconductor Capacitors, Semiconductor Resistor Model (R), Elementary Devices
@subsection Capacitors
@ -6112,7 +6197,38 @@ values above may be node names in the running circuit, or real values.
If more than one condition is given, e.g. stop after 4 when @math{v(1) > 4}
when @math{v(2) < 2}, the conjunction of the conditions is implied.
@subsection Sysinfo: Print system information
General Form:
@example
sysinfo
@end example
The command prints system information useful for sending bug report
to developers. Information consists of:
@itemize @bullet
@item Name of the operating system,
@item Name of the node,
@item Current release of the operating system,
@item Current version of this release,
@item Name of hardware type.
@end itemize
The example below shows the use of this command.
@example
ngspice 1 -> sysinfo
Linux janus.wayout.net 2.4.20 #1 SMP Tue Jun 10 18:58:26 CEST 2003 i686
ngspice 2 ->
@end example
@strong{Note:} This command may not be available on your environment, if
it is not available, please send analogous information when submitting
bug reports.
@node Tf, Trace, Stop, Commands
@subsection Tf*: Run a Transfer Function analysis