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SLSMODNAMEDESCRIPTIONEXAMPLESEE ALSONAME |
slsmod - process file for sls
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DESCRIPTION |
The file slsmod contains the process information
for the sls simulator. This file is used by
sls when a simulation is done at level 2 or level
3.
The following variables are used in an slsmod
process file:
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vh
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The positive supply voltage in the circuit (vl = 0 is
assumed).
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vswitch
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Switching voltage for O to I and I to O transitions. If
this variable is not specified, vswitch = vh/2 is used.
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vminh
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Minimum stable voltage for a logic I state.
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vmaxl
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Maximum stable voltage for a logic O state.
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krise
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Factor with which RC time constants for rising voltages
are multiplied during timing simulation.
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kfall
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Factor with which RC time constants for falling voltages
are multiplied during timing simulation.
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loffset
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Value which has to be subtracted from the
layout-specified length of a transistor to gain the
effective length of the transistor.
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woffset
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Value which has to be subtracted from the
layout-specified width of a transistor to gain the effective
width of the transistor.
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rstat
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The resistance between drain and source used for stable
voltage determination.
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rsatu
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The same resistance but now for the saturated case. A
transistor is said to be saturated when - after an initial
calculation with rstat resistances - it appears that Vdrain
or Vsource > vswitch (for nenh transistors) or Vdrain or
Vsource < vswitch (for penh transistors).
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cgstat
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The gate capacitance of the transistor used for stable
voltage determination.
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cgrise
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The gate capacitance of the transistor used for rise
time calculations.
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cgfall
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The gate capacitance of the transistor used for fall
time calculations.
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cestat
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The drain or source capacitance of the transistor used
for stable voltage determination.
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cerise
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The drain or source capacitance of the transistor used
for rise time calculations.
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cefall
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The drain or source capacitance of the transistor used
for fall time calculations.
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rdyn
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The resistance between source and drain used for rise
and fall time calculations.
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cch
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The drain or source capacitance of the transistor which
is used in addition to cerise or cefall during
rise and fall time calculations. However, this capacitance
is only used if the transistor is conducting.
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First the general simulation parameters vh,
(eventually vswitch), vminh, vmaxl,
krise and kkfall are specified in the
slsmod file. Next, the other parameters - which are
the transistor model parameters - are specified. Transistor model parameters can be specified for a nenh,
a penh and a ndep transistor. Each of these parameter
specifications might be omitted but their order is
fixed. For each transistor first a specification of
loffset and woffset is done. Then the other
variables are specified by giving their value for some
typical transistor dimensions. This is done by first
specifying the values for a minimum width and length and
then specifying the values for a width and length that only
differ from the first width and length by that the width is
larger or that the length is larger. In order to obtain the parameters for transistors that
have dimensions that are not enumerated, sls will
perform an interpolation. For each transistor there is one general parameter
specification list and several mode parameter specification
lists. The general specification list contains the values
for rstat, cgstat, cgrise,
cgfall, cestat, cerise and
cefall, and the mode specification lists contain the
values for rdyn and cch. For the nenh transistor and the penh transistor
rdyn and cch have to be specified for the
following modes: |
pullup
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A transistor is in the pullup mode when there is static
current flow through it and when a time constant for a
falling voltage is determined.
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pulldown
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A transistor is in the pulldown mode when there is
static current flow through it and when a time constant for
a falling voltage is determined.
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passup
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A transistor is in the passup mode when there is no
static current flow through it and when a time constant for
a rising voltage is determined.
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passdown
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A transistor is in the passdown mode when there is no
static current flow through it and when a time constant for
a falling voltage is determined.
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Whether or not there is a static current flow through a
transistor is determined by considering all transistors to
be "on". For an ndep transistor rdyn and cch have
to be specified for the modes: |
load
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A transistor is in the load mode when its gate is
connected to its drain or source (via a resistor).
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superload
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A transistor is in the superload mode when its gate is
not connected to its drain or source (via a resistor).
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EXAMPLE |
Below an example of a slsmod file for a NMOS process is
given.
/* process : nmos4u700A TU-Delft
/* author : A.J. Schooneveld, TU-Delft
/* date : 6 May 1987
*/
vh=5
vminh=4
vmaxl=1
krise=0.90
kfall=0.66
nenh
loffset=0.625u
woffset=0.88u
w=6u l=4u : rstat=4.97k rsatu=25.4k
cgstat=13.0f cgrise=9.2f
cgfall=12.0f cestat=2.2f
cerise=2.4f cefall=2.9f
w=15u l=4u : rstat=1.69k rsatu=6.95k
cgstat=48.8f cgrise=24.2f
cgfall=38.0f cestat=6.3f
cerise=5.6f cefall=8.9f
w=30u l=4u : rstat=0.832k rsatu=3.19k
cgstat=92.1f cgrise=54.1f
cgfall=82.2f cestat=12.8f
cerise=11.8f cefall=15.0f
pullup
/* not determined */
w=6u l=4u : rdyn=22.3k cch=8.7f
w=15u l=4u : rdyn=5.3k cch=31.8f
w=30u l=4u : rdyn=2.2k cch=53.3f
end
pulldown
w=6u l=4u : rdyn=22.3k cch=8.7f
w=15u l=4u : rdyn=5.3k cch=31.8f
w=30u l=4u : rdyn=2.2k cch=53.3f
end
passup
w=8u l=4u : rdyn=7.94k cch=4.62f
end
passdown
w=8u l=4u : rdyn=5.24k cch=5.29f
end
end
ndep
loffset=0.605u
woffset=1.2u
w=6u l=4u : rstat=29.2k rsatu=29.2k
cgstat=7.8f cgrise=10.7f
cgfall=23.4f cestat=0f
cerise=0f cefall=0f
w=6u l=10u : rstat=76.5k rsatu=76.5k
cgstat=11.7f cgrise=19.8f
cgfall=28.2f cestat=0f
cerise=0f cefall=0f
w=12u l=4u : rstat=10.2k rsatu=10.2k
cgstat=16.4f cgrise=31.7f
cgfall=46.0f cestat=0f
cerise=0f cefall=0f
load
w=6u l=4u : rdyn=25.5k cch=-3.6f
w=6u l=10u : rdyn=66.3k cch=-14.9f
w=12u l=4u : rdyn=8.7k cch=-15.9f
end
superload
w=12u l=4u : rdyn=3.63k cch=-15.6f
end
end
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SEE ALSO |
A.J. Schooneveld, "Determination of SLS transistor
model parameters", Delft University of Technology,
sls(1ICD).
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