diff --git a/ChangeLog b/ChangeLog index 2d7debb6f..f5dda52d0 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,6 +1,16 @@ +2003-09-20 Paolo Nenzi + + * 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 - * 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(). diff --git a/DEVICES b/DEVICES index a2cd4b2be..57954fa53 100644 --- a/DEVICES +++ b/DEVICES @@ -10,11 +10,29 @@ This file it is useful in writing ngspice documentation. ************************* Linear devices ******************************** *************************************************************************** -CAP - Capacitor - Initial Release - -IND - Inductor - Initial Release +CAP - Capacitor + 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/ - \ No newline at end of file + diff --git a/doc/ngspice.texi b/doc/ngspice.texi index 5961e37e2..ce6a9b21a 100644 --- a/doc/ngspice.texi +++ b/doc/ngspice.texi @@ -1770,10 +1770,10 @@ in the direction of voltage drop). General form: @example - RXXXXXXX N1 N2 VALUE + RXXXXXXX n+ n- value + + @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 @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. + +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 -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. +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. -Note: ac parameter can be considered "safe" since rework-11 - Scale parameter is not applied to l,w and other geometric - parameters. +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 - m= + RXXXXXXX n+ n- + + m= @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